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Wang, Xueyun Sharon. "NMR relaxation study of the interaction of N-alkyl nicotinamides with micelles." Scholarly Commons, 1992. https://scholarlycommons.pacific.edu/uop_etds/2233.
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The mobility of N-alkyl nicotinamides and their solubilization equilibria in surfactant micellar solution were investigated using an NMR paramagnetic relaxation method. The spin-lattice relaxation times (Tl) . for protons of these compounds were measured in pure D20 and in cationic surfactant solution in the presence and absence of · a low concentration of paramagnetic Ma2+ ions. The rotational motion of these molecules in aqueous phase became slower when the alkyl group changed from methyl to octyl. The increase of the 1H spinlattice relaxation rate (Rl) of the molecules, when surfactants are added, implies the penetration of these solubilizates into micellar phase. The micelle to water phase distribution coefficient, 1-p, was determined by monitoring the change of Rl of the solubilizates upon addition of paramagnetic ions to the aqueous phase. The mole fraction based distribution coefficient, Kx, as well as the free energy of transfer of N-alkyl nicotinamides from the aqueous phase to the micellar phase were calculated. A model was postulated for the interaction of N -alkyl nicotinamide with micelles. Hydrophobic force between the alkyl chains of the solubilizates and the surfactants accounts for the solubilization of N -alkyl nicotinamides and can force the binding of cationic compounds to cationic micelles · despite charge repulsion. With increasing of the alkyl chain length, the hydrophobic force increases, and the interaction between them becomes stronger, and more N -alkyl nicotinamides are solubilizated into the micellar phase.
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Dennis, Kim Jason. "Use of isomerizable N-alkylmerocyanine dyes to robe molecular interactions within micellar solubilization sites." Scholarly Commons, 1986. https://scholarlycommons.pacific.edu/uop_etds/2116.
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Effects of aqueous surfactant solutions upon cis/trans isomerization reactions of various N-alkyl-merocyanine dyes (II) were studied. Dramatic rate enhancements were found for all dyes in CTAB and SDS solutions above the CMC. CTAB solutions showed the greatest effect with some dye isomerizations catalyzed in excess of 1000-fold. Increases in either CTAB concentration or dye isomerization rates. N-methyl through N-pentyl dye isomerization rates were measured as a function of CTAB concentration and the data treated according to the pseudophase model for micellar catalysis. KS values ranged from 198 to 2000 M-1 for N-methyl to N-pentyl dyes, respectively. Micellar rate constants also increased as dye hydrophobicity was increased. Thermodynamic activation parameters were determined for N-methyl through N-hexylmerocyanine dyes in CTAB solutions. Rate enhancements in CTAB (above the CMC) relative to those in purely aqueous solutions were shown to be due to a substantial lowering of ΔH‡, for the various dyes. Increased CTAB concentrations of N-methyl dye solutions gave reaction rate increases resulting from a lowering of ΔS‡. In 0.054 M CTAB, increases in reaction rates with increased N-alkyl chain length were due to large increases ΔS‡ (from ca. 0 eu for N-methyl to 13 eu for N-hexyl). The data were discussed in terms of molecular interactions which can occur within the micellar solubilization sites.
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Stoja, Obradović. "Termodinamička stabilnost binarnih mešovitih micela odabranih homologa iz grupa Brij surfaktanata i polisorbata." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104920&source=NDLTD&language=en.
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Uloga micela u razvoju farmaceutskih oblika zasniva se na njihovom potencijalu da kao transportni sistemi povećaju bioraspoloživost lekovite supstance i unaprede njen farmakokinetski profil. Micele mogu da modifikuju propustljivost biološkuh membrana, omoguće kontrolisano oslobađanje lekovite supstance iz farmaceutskog oblika, stabilizuju lekovitu supstancu, itd. Kombinovanje različitih surfaktanata kao gradivih jedinica omogućava konstruisanje micela sa poželjnim fizičko-hemijskim karakteristikama. Takođe, mešovite micele između čijih gradivnih jedinica postoje sinergističke interakcije se formiraju na nižim koncentracijama surfaktanata u poređenju sa monokomponentnim micelama. U doktorskoj disertaciji je ispitana termodinamička stabilnost binarnih mešovitih micela Brij S10 i Brij S20 surfaktanata sa polisorbatom 20, polisorbatom 60 i polisorbatom 80 kao kosurfaktantima. Analiziran je uticaj građe odabranih nejonskih surfaktanata na fizičko-hemijske parametre i stabilnost njihovih mešovitih micela. Vrednosti kritične micelarne koncentracije su dobijene spektrofluorimetrijskim merenjima. Da bi se analizirao uticaj temperature na termodinamičku stabilnost micela, merenja su vršena na sledećim temperaturama: 273.15 K, 283.15 K, 293.15 K, 303.15 K i 313.15 K. Rezultati su tumačeni sa aspekta teorije regularnih rastvora (regular solution theory – RST), uz primenu Porterove jednačine. Na osnovu rezultata istraživanja, predloženi su modeli monokomponentnih i binarnih mešovitih micela. Utvrđeno je da u svim analiziranim binarnim mešovitim sistemima postoji dodatna entropija. Može se doneti zaključak da pretpostavka RST o isključivo entalpijskoj prirodi dodatne Gibsove energije nije primenljiva na ispitivane binarne sisteme. Utvrđeno je da postojanje razlike u dužini hidrofobnih segmenata monomera dodatno stabilizuje mešovitu micelu. Sa porastom temperature, ovaj stabilizacioni efekat entropijskog porekla postaje izraženiji. Prisustvo dvostruke veze u ugljovodoničnom lancu polisorbata 80 doprinosi povećanoj rigidnosti njegovih molekula. Rezultat je smanjena termodinamička stabilnost mešovitih micela koje sadrže polisorbat 80 u poređenju sa mešovitim micelama koje sadrže njegov zasićeni homolog, polisorbat 60. Utvrđeno je da razlika u dužini polarnih segmenata monomera koji grade mešovitu micelu utiče na stepen hidratacije micele, a time i na njenu stabilnost.The role of the micelles in pharmaceutical formulation lies in their ability to, when used as drug delivery systems, increase the bioavailability of the drug and enhance its pharmacokinetic profile. Micelles may modify the permeability of biomembranes, enable controlled release from drug delivery systems, stabilize the drug, etc. By combining different surfactants as building units it is possible to engineer micelles with favorable physicochemical characteristics. Also, the mixed micelles between whose building units synergistic interactions exist are formed on lower concentrations of surfactants in comparison to single-component micelles. In the doctoral dissertation the thermodynamic stability of binary mixed micelles built of Brij S10 and Brij S20 with polysorbate 20, polysorbate 60 and polysorbate 80 as co-surfactants is examined. The influence of the structure of selected nonionic surfactants on physicochemical parameters and the stability of their mixed micelles is analyzed. Critical micelle concentration values were obtained by spectrofluorimetric measurements. In order to analyze the influence of the temperature on the micelles’ thermodynamic stability, measurements were conducted on following temperatures: 273.15 K, 283.15 K, 293.15 K, 303.15 K and 313.15 K. Obtained results were studied using regular solution theory (RST) and Porter’s equation. Based on the research results, models of both single-component and binary mixed micelles are introduced. It is deduced that in all analyzed binary mixed systems the excess entropy exists. A conclusion can be made that the assumption of RST regarding solely enthalpic nature of the excess Gibbs energy is not applicable to investigated binary systems. The difference in the length of the hydrophobic segments of monomers additionally stabilizes the mixed micelle. With the increase in the temperature, this stabilizing effect of the entropic nature is more noticeable. The existence of the double bond in polysorbate 80 hydrocarbon chain contributes to the increased rigidity of its molecules. As a result, the thermodynamic stability of the mixed micelles containing polysorbate 80 is lesser than the stability of the mixed micelles containing its saturated homologue, polysorbate 60. It is determined that the difference in length of polar segments of mixed micelle monomers affects the micelle hydration and therefore, its stability.
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Kosta, Popović. "Termodinamička stabilnost odabranih micelarnih sistema žučnih soli značajnih za nove farmaceutske formulacije." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104270&source=NDLTD&language=en.
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Da bi se dobio sistem surfaktanata željenih osobina moguće je hemijski modifikovati već postojeće molekule površinski aktivnih supstanci, a druga mogućnost je konstrukcija binarnih smeša surfaktanata. U farmaceutskoj i prehrambenoj industriji uveliko se primenjuju binarne smeše površinski aktivnih molekula. Ukoliko je binarna mešovita micela termodinamički stabilnija od hipotetičke idealne binarne mešovite micele, onda je kritična micelarna koncentracija binarne smeše surfaktanata niža čak i od hidrofobnije gradivne jedinice mešovite micele, što znači da je za isti efekat površinske aktivnosti potrebna manja količina binarne smeše nego čistog surfaktanta. Različite gradivne jedinice binarne micele u micelarnoj pseudofazi mogu formirati specifične regije koje mogu vezivati lekove određenih strukturnih karakteristika. Pogodno je da jedna gradivna jedinica bude krute konformacije, npr. soli žučnih kiselina, dok je druga gradivna jedinica konformaciono pokretljiva (ugljovodonični nizovi iznad C10). Na taj način se povećava zapremina hidrofobne micelarne faze u odnosu na zapreminu hidrofobne micelarne faze monokomponentne micelle konformaciono krutog surfaktanta, što povećava solubilizacioni kapacitet mešovite micele u odnosu na monokomponentnu micelu krutog surfaktanta. Povećanjem dužine ugljovodoničnog niza konformaciono pokretnog surfaktanta povećava se stepen unutrašnje pokretljivosti u hidrofobnom domenu mešovite micele, što takođe povećava verovatnoću prihvatanja molekula gosta. Micelarni sistemi, kako monokomponentnih micela tako i binarnih mešovitih micela dodatno se mogu termodinamički stabilizovati povećanjem jonske jačine rastvora. Za hidrataciju katjona troše se molekuli vode iz sistema, što povećava efekat desolvatizacije hidrofobne površine surfaktanata, pa se zbog toga pospešuje samoasocijacija.To obtain the surfactant system with the desired properties it is possible to chemically modify existing molecules of surface active agents. The other possibility is the construction of binary mixtures of surfactants. Binary mixtures of surface active molecules are widely used In the pharmaceutical and food industry. If the binary mixture micelle is more thermodynamically stable than the hypothetical ideal binary mixed micelle, then the critical micellar concentration (CMC) of the binary mixture of surfactants is even lower than the CMC of the more hydrophobic building block of the binary mixture. That means that for the same effect of surface activity less the amount of the binary mixture than the pure surfactants is required. The different building blocks of binary micelles in micelar pseudophase can form specific regions that can bind drugs of certain structural characteristics. It is suitable that one building block is of a rigid conformation, i.e. bile acid salts, while the second building block is of a flexible conformation (above C10 hydrocarbon arrays). In this way the volume of the hydrophobic micellar phase is increased in relation to the volume of the hydrophobic micellar phase of the monocomponent micelles of conformationally rigid surfactant, which increases the capacity of solubilisation of the mixed micelles, compared to the mono-component surfactant micelle of the rigid conformation. By increasing the length of the hydrocarbon array of the the conformational flexible surfactant, the degree of internal mobility in the hydrophobic domain of mixed micelles is also increased, which also increases the likelihood of acceptance of guest molecules. Micellar systems, of both monocomponent micelles and mixed micelles can be additionally thermodynamically stabilized by increasing the ionic strength of the solution. The hydration of cations uses the molecules of water from the system, which increases the effect of desolvatisation of the hydrophobic surface of the surfactants, and therefore promotes self-association.
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Mousseau, Kenneth Scott. "Determination of critical micelle concentration of an amphiphilic siderophore." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/mousseau/MousseauK0809.pdf.
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The sodachelins are a group of six amphiphilic siderophores produced by a halophilic bacterium. Amphiphilic siderophores, such as the sodachelins, are important in the solubilization and sequestration of iron related to microbial metabolism and are also unique in their ability to form micelle and vesicular structures. This professional paper describes siderophore importance in iron bioavailability, siderophore chemistry and biological function and a thermodynamic analysis of forces that drive micellization and vesicle formation. A description of experiments conducted to isolate, separate and purify the sodachelins for the purpose of measuring their critical micelle concentration (CMC) follows the review of literature. Initial siderophore isolation was achieved using XAD-2 resin to generate a crude extract. This crude extract was then purified by HPLC, and the measurement of CMC of a single siderophore, sodachelin E, was performed with a tensiomat instrument. Crude separation by XAD resin was proven successful; XAD resin has a strong affinity for siderophores as shown by experiment with the siderophore desferrioxamine B (DFB) as a control. Purification of the crude siderophore extract by only one pass on the HPLC was proven insufficient to generate a single, pure siderophore. At least a second pass on the HPLC is required to remove all contaminants. The protocol developed for CMC analysis is consistent and accurate based on a sodium dodecyl sulfate (SDS) control experiment. An approximate CMC value of 140 micron for sodachelin E was obtained, however, HPLC analysis showed contamination of another sodachelin and possible other organic solutes, indicating that this value may be inaccurate.
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Kitchens, Christopher Lawrence Roberts Christopher B. "Metallic nanoparticle synthesis within reverse micellar micromulsion systems." Auburn, Ala., 2004. http://repo.lib.auburn.edu/EtdRoot/2004/FALL/Chemical_Engineering/Dissertation/kitchcl_13_Dissertation(abbrv).pdf.
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Slaymaker, Elizabeth Ann. "Effects of surface active agents on drop size in liquid-liquid systems." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/10260.
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Tucker, Ian Malcolm. "The surface and solution properties of complex mixed surfactant systems." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670103.
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Staggemeier, Bethany Ann. "Dynamic surface tension detection : novel applications to continuous flow analysis and interfacial analysis /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/11584.
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Howell, Desiree Pearl. "Evaluation of surfactants for the enhancement of PCB degradation." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20746.
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Fitzgerald, Paul A. "Solution behaviour of polyethylene oxide, nonionic gemini surfactants." Connect to full text, 2002. http://setis.library.usyd.edu.au/adt/public_html/adt-NU/public/adt-NU20031219.162500/index.html.
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Zhang, Huixian. "Multicomponent diffusion of macromolucule-additive and drug-surfactant aqueous ternary systems." [Fort Worth, Tex.] : Texas Christian University, 2009. http://etd.tcu.edu/etdfiles/available/etd-04292009-164431/unrestricted/Zhang.pdf.
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Pitt, Darren William. "Design of polymer systems and surface-active agents for the improvement of cell attachment for treatment of ocular diseases." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/380880/.
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The degradation of eyesight is a frightening experience for individuals and unfortunately gradual loss of vision with old age is commonplace. One of the most common forms of eye disease which effects vision is Age-Related Macular Degeneration (AMD). AMD is the leading cause of blindness in the developed world and there is currently no cure for the disease. One treatment option available for the neovascular form of AMD is the injection of Bevacizumab [an anti-vascular endothelial growth factor (VEGF) drug] into the eye on a monthly basis. Investigation into the biodegradable polymers poly(L-lactic acid) (PLLA) and poly(D,L-lactic-co-glycolic acid) (PLGA) as a possible drug delivery system with highly uniform and reproducible microspheres was developed. Under optimised parameters Bevacizumab-encapsulated PLLA:PLGA microspheres were successfully prepared with a steady release of Bevacizumab being obtained. Additionally, fibrous scaffolds of methyl methacrylate (MMA) and poly(ethylene glycol) methacrylate (PEGM) were prepared by an electrospinning process. These MMA:PEGM co-polymers were investigated as a possible Bruchs membrane replacement and as the support for retinal pigment epithelium (RPE) transplantation. The MMA:PEGM co-polymers were functionalised with N-succinimidyl which resulted in the fibres forming a gel in vitro. Gel formation was examined further and successful RPE cell attachment and growth onto these gels was observed. Further work on surface active agents was undertaken to improve the cell adhesion, proliferation and growth of RPE cells onto these methacrylate based frameworks. An arginine-glycine-aspartic acid (RGD) peptidomimetic was prepared and reacted onto the surface of the MMA:PEGM co-polymers, however, the peptidomimetic-attached MMA:PEGM fibres offered little improvement in cell growth in comparison with N-succinimidyl–activated MMA:PEGM co-polymer fibres. Additional attachment of the natural proteins laminin, collagen and fibronectin onto the microspheres was achieved. Attachment of these proteins prolonged the release of the dye from the microspheres and showed no cytotoxic effects when examined in-vitro.
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Da, Rocha Sandro Roberto Possatti. "CO₂-water interface : interfacial tension, emulsions, microemulsions, and computer simulations /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004246.
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Santonicola, Mariagabriella. "Molecular self-assembly and interactions in solutions of membrane proteins and surfactants." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 248 p, 2007. http://proquest.umi.com/pqdweb?did=1257806151&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Thesis (Ph.D.)--University of Delaware, 2006.Principal faculty advisors: Eric W. Kaler, College of Engineering; and Abraham M. Lenhoff, Dept. of Chemical Engineering. Includes bibliographical references.
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Nydén, Magnus. "NMR diffusion studies of microheterogeneous systems surfactant solutions, polymers solutions and gels /." Lund : University of Lund, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945132.html.
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Dejan, Ćirin. "Fizičko-hemijske karakteristike mešovitih micela soli žučnih kiselina i nejonskih surfaktanata." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=92790&source=NDLTD&language=en.
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Surfaktanti imaju značajnu primenu u farmaciji i medicini. Ove supstance se primenjuju u farmakoterapiji, koriste se za solubilizaciju hidrofobnih lekova, a pojedina ispitivanja pokazuju da mogu unaprediti bioraspoloživost određenih aktivnih supstanci. U poslednje vreme se sve više pažnje posvećuje ispitivanju smeša surfaktanata, pošto je utvrđeno da sistemi dva ili više surfaktanta često pokazuju poželjnija svojstva od pojedinačnih surfaktanata za aplikaciju u farmaciji i medicini. U ovoj disertaciji su ispitivani binarni sistemi osam anjona žučnih kiselina i dva nejonska surfaktanta (polisorbat 40 i polisorbat 80). Ciljevi su određivanje vrednosti kritičnih micelarnih koncentracija ispitivanih smeša surfaktanta, utvrđivanje međudejstva između različitih surfaktanta u njihovim mešovitim micelama, kao i ispitivanje uticaja stukture ispitivanih surfaktanata na fizičko-hemijske karakteristike mešovitih micela. Rezultati pokazuju da ispitivane smeše imaju znatno niže vrednosti kritičnih micelarnih koncentracija od anjona žučnih kiselina. Smeše anjona žučnih kiselina i polisorbata 40 imaju manje vrednosti eksperimentalnih kritičnih micelarnih koncentracija, od izračunatih, idealnih, vrednosti, što ukazuje na postojanje sinergističkih interakcija u mešovitim micelama. Smeše anjona žučnih kiselina i polisorbata 80 imaju uglavnom veće vrednosti kritičnih micelarnih koncentracija od idealnih vrednosti, što može biti posledica postojanja antagonističkih interakcija između gradivnih jedinica mešovitih micela. Vrednosti interakcija, koje dovode do neidealnog ponašanja sistema surfaktanata, su određene računanjem vrednosti interakcionog parametra, β1,2, prema regular solution theory. Sistemi anjona žučnih kiselina i polisorbata 40 imaju negativne vrednosti interakcionog parametra, dok sistemi anjona žučnih kiselina i polisorbata 80 imaju uglavnom pozitivne vrednosti interakcionog parametra. Poređenjem fizičko-hemijskih parametara mešovitih micela je utvrđeno da postojanje privlačnih međudejstava između hidrofilnih delova različitih surfaktanata najverovatnije potiče od vodoničnih veza koje se formiraju između hidrofilnih grupa anjona žučnih kiselina i polioksietilenskih delova. Pozitivne vrednosti β1,2 parametra su najverovatnije posledica sterno krute cis dvostruke veze oleinske kiseline u molekulu polisorbata 80, usled čega se lipofilni deo ovog nejonskog surfaktanta teže pakuje u jezgru mešovitih micela. Pretpostavlja se da zbog toga dolazi do formiranja dimera anjona žučnih kiselina u mešovitim micelama u kojima se javljaju odbojne interakcije između negativno naelektrisanih karboksilatnih grupa.Surfactants have important application in pharmacy and medicine. These substances are applied in pharmacotherapy, they are used for hydrophobic drug solubilisation, and certain investigations indicate they can improve bioavailability of certain active substances. Lately, investigations of surfactant mixtures have gained a lot of attention, since it was found that systems of two or more surfactants often show more desirable properties than the individual surfactants, for application in pharmacy and medicine. In this dissertation, binary systems of eight bile acid anions and two nonionic surfactants (polysorbate 40 and polysorbate 80) were investigated. The aims were to determine values of critical micelle concentrations of investigated surfactant mixtures, interactions between different surfactants in their mixed micelles, and to investigate the influence of the structure of investigated surfactants on physico-chemical characteristics of mixed micelles. The results indicate that investigated mixtures have significantly lower values of critical micelle concentrations than bile acid anions. Mixtures of bile acid anions and polysorbate 40 have lower values of experimentally obtained critical micelle concentrations than the calculated, ideal, values, indicating the existence of synergistic interactions in mixed micelles. Mixtures of bile acid anions and polysorbate 80 have mainly higher values of critical micelle concentrations than the ideal values, what could be due to the existence of antagonistic interactions between building units of mixed micelles. The values of the interactions, attributing to the nonideal behaviour of the surfactant systems were obtained by calculating the values of the interaction parameter, β1,2 , according to the regular solution theory. Systems of bile acid anions and polysorbate 40 have negative values of the interaction parameter, while systems of bile acid anions and polysorbate 80 have mainly positive values of interaction parameter. By comparing the physico-chemical parameters of mixed micelles, it was determined that existence of attractive interactions between hydrophilic parts of different surfactants most probably originates from the hydrogen bonds, which are formed between hydrophilic groups of bile acid anions and polyoxyethylene parts. Positive values of β1,2 parameter are most probably due to sterically rigid cis double bond of oleic acid in polysorbate 80 molecule, causing the lipophilic tail of this nonionic surfactant to pack less easily in the core of mixed micelles. It is hypothesised that this influences formation of dimers of bile acid anions in mixed micelles, where repulsive interactions emerge between negatively charged carboxylate groups.
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Risley, Mason J. "Surfactant-assisted exfoliation and processing of graphite and graphene." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/48980.
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Surfactant assisted solution exfoliation of expanded graphite by means of sonication was carried out in an attempt to produce non-covalent charge functionality on the surface of graphene for the directed self assembly of graphene films on patterned substrates via electrostatic interactions. This thesis includes the results of experimental research associated with: 1) quantifying the effectiveness of various di-functionalized dithienothiophene surfactant small molecules, 2) further understanding the surface affinity and interaction mechanism between these surfactant molecules and the surface of expanded graphite and graphene and 3) experimentally testing the feasibility of the directed self-assembly of graphene films by means of charge functionalization of graphene by the surfactant molecules adsorbed onto the surface of exfoliated graphene.
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Ivana, Vapa. "Uticaj dužine hidrofobnog segmenta homolognih polisorbata na termodinamičke parametre binarnih mešovitih micela polisorbata i Tritona X-100." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2016. https://www.cris.uns.ac.rs/record.jsf?recordId=101126&source=NDLTD&language=en.
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Binarne mešovite micele su značajne u farmaceutsko-farmakološkim primenama, u kojima lek kao površinska aktivna supstanca može da bude gradivna jedinica binarne micelle (promena bioraspoloživosti, mehanizam resorpcije itd.). Takođe su važne i mešovite micele kod kojih su gradivne jedinice biosurfaktanti (biokompatibilni solubilizatori lekova). U kozmetičkoj, prehrambenoj i industriji detergenata mešovite micele su uveliko zastupljene. Važno je nalaženje binarnih sistema surfaktanata koji u mešovitim micelama poseduju sinergističko međudelovanje (negativna vrednost interakcionog parametra). Takva binarna smeša surfaktanata ima nižu vrednost kritične micelarne koncentracije od hidrofobnije komponente smeše. U prvom delu rada je ispitivan uticaj dužine hidrofobnog segmenta homolognih Tween-ova iz mešovitih micela sa Triton-om X100 na interakcioni parametra ( i, j β ) i dodatnu Gibbs-ovu energiju (GE ), takođe ispitivao se i uticaj temperature na stabilnost proučavanih mešovitih micela (273,15-328,115 K). Kritične micelarne koncentracije čistih surfaktanata i njihovih binarnih smeša su određeni spektrofluorometrijski uz primenu pirena kao probnog molekula. Nađeno je da na svakoj ispitivanoj temperaturi povećanje dužine zasićenog alifatičnog niza polisorbata povećava stabilnost mešovite micele ( , 0 i j β < i GE < 0 ) u odnosu na idealnu mešovitu micelu. Prisustvo C9 dvostruke veze u ostatku oleinske kiseline Tween-a 80 umanjuje sinergistički efekat ovog polisorbata u odnosu na Tween 60, koji ima hidrofobni segment sa istim brojem C atoma, ali bez olefinske veze. Dodatna slobodna entalpija ispod temperature 298.15 K određena je entropijskim doprinosem, a iznad 298.15 K entalpijskim doprinosom. U drugom delu rada ispitivane su binarne smeše surfaktanata Tween 85/Triton X100 i Tween 85/Triton X165 u vodenom rastvoru u intervalu temperature od 273.15 K do 323.15 K. Pri temperaturama od 273.15 K i 283.15 K između različitih gradivnih jedinica binarnih mešovitih micela postoje sinergističke interakcije na čiju veličinu ne utiče razlika u dužini polioksietlienskih nizova Triton-a X100 i Triton-a X165. Na većim vrednostima temperature duži polioksietilenski niz Triton-a X165 pokazuje stabilizirajuči efekat u mešovitoj miceli sa Tween-om 85 u odnosu na mešovite micele Tween 85/Triton X100. Kod ispitivanih binarnim mešovitim micela ne može se prihvatiti aproksimacija regularnih smeša o nula vrednosti dodatne entropije formiranja binarne mešovite micele.Binary micelles are important in pharmaceutical-pharmacological applications, in which drug as surface active substance can be building unit of binary micelle (influencing bioavailability change, change of resorption mechanism etc.). Mixed micelles in which building units are biosurfactants (biocompatible drug solubilizers) are also important. In cosmetics, food and detergent industry mixed micelles are widely present. It is important to find binary surfactant systems having synergistic interactions (negative value of interaction parameter). That binary surfactant mixture has lower critical micelle concentration value than more hydrophobic component of the mixture. In the first parth of this work, influence of hydrophobic segment length of homologues Tweens in mixed micelles with Triton X-100 on the interaction parameter value ( i, j β ) and an excess Gibbs energy (GE ) was investigated. Also, influence of temperature on the stability of investigated mixed micelles has been investigated (273.15-328.15 K). Critical micelle concentration values of pure surfactants and their binary mixtures were determined spectrofluorimetrically using pyrene as a probe molecule. It was found for every investigated temperature that increase in length of saturated aliphatic side chain of a polisorbate increases the stability of investigated mixed micelles (β < and GE < 0 ) compared to ideal mixed micelles. Presence of the C9 double bond in oleic acid residue of Tween 80 reduces synergistic effect of this polysorbate compared to Tween 60 which contains hydrophobic segment with the same number of C atoms but without olefin bond. Excess free enthalpy below the 298.15 K is determined with entropic contribution, but above 298.15 K with enthalpic contribution. In the second parth of this work, binary surfactant mixtures of Tween 85/Triton X100 and Tween 85/Triton X165 have been investigated in water solution in the temperature range from 273.15 K to 323.15 K. At the temperatures of 273.15 K and 283.15 K between different building units of binary mixed micelles synergistic interactions exist, which size is not affected by difference in length of the polyoxyethylene chains. At higher temperatures, longer polyoxyethylene chain of Triton X165 shows more stabilizing effect in mixed micelle with Tween 85 than in mixed micelles of Tween 85/Triton X100. For investigated binary mixed micelles, regular solution theory approximation about zero value of excess entropy of binary mixed micelle formation cannot be accepted.
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Samakande, Austin. "Synthesis and characterization of surfmers for the synthesis of polystyrene-clay nanocomposites." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1188.
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Hill, Gavin T. H. "The preparation and testing of novel biodegradable surfactants using poly(lactic acid) as the backbone, by a one-step ring opening polymerisation reaction." Thesis, University of St Andrews, 2009. http://hdl.handle.net/10023/746.
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A review of the chemistry of poly(lactic acid) was carried out with a focus on techniques and applications of PLA polymer and copolymers with reference to some of the work that has been accomplished over the last 20 years or so. A review of the characterisation techniques used to analyse PLA polymers and copolymers was also carried out giving reference to the equipment and methods used herein. An investigation into the potential of PLA as the hydrophilic portion of a polymeric surfactant was carried out. To develop PLA based surfactants, the ring opening polymerisation of lactide was carried out in a melt in the presence of a long chain alcohol (C₇ to C₂₀) or diol (C₄ & C₆) to produce AB or ABA type polymers that follow the traditional surfactant template. Stannous octanoate and 4-dimethylaminopyridine were typically used as catalysts due to their high activity and relative cheapness. PLA only shows good hydrophilicity with up to 12 lactic acid units in the chain. Above this the electrostatic interactions between polymer chains reduced water solubility. It was also noted that D,L-lactide produced more water soluble polymers (syndiotactic) than the enantiomerically pure L-lactide (isotactic polymer chains). An investigation of the hydrophobic properties of PLA was carried out to evaluate their usefulness for other biodegradable surfactant applications. To this end an investigation of sugars as the hydrophilic portion of the molecule was carried out. Due to problems with solubilising sugars, they were deemed unsuitable for use as initiatiors within the scope of this research. Choline chloride was then investigated as a potential hydrophilic initiator and indeed has produced some of the most water soluble of PLA polymers. Choline chloride presented several challenges as an initiator, its high melting point resulted in polar solvents such as t-butanol being employed. Alternatively, more success was achieved by preparation of a choline chloride eutectic mixture prior to the polymerisation. It was discovered that a choline chloride/urea eutectic mixture was capable of self initiation, thus required no further addition of catalyst, this result shows a potential step forward in PLA green chemistry. A final investigation into producing surface-active PLA in a one-pot process that required only a hydroxycarboxylate initiator was carried out. The production of PLA sodium or potassium salts was carried out in a melt polymerisation and the results show some promise. Initiators that have been employed include a range of a, b and g-hydroxycarboxylic acids. These work through tautomerisation to the alkoxide, which then initiates a living type polymerisation of lactide to produce surface-active polymers. As well as the synthesis of these polymers some analysis of the physical and aqueous properties of these materials was carried out. PLA sodium salts were shown to have reasonable surfactant ability (~45 mNm⁻¹) and low CMC values of around 5x10⁻⁹ mol cm⁻³. They were also shown to have some properties as emulsifiers, and in some cases showed non-Newtonian fluid behaviour such as shear-thinning (thixotropy) and shear-thickening (dilatant). The thermal characteristics of the polymers such as T[subscript]g and stability were assessed as well as their ability to retain water.
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Zhang, Ying. "Correlations among surfactant drag reduction additive chemical structures, rheological properties and microstructures in water and water/co-solvent systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124255735.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xxxiv, 429 p.; also includes graphics (some col.). Includes bibliographical references (p. 402-429). Available online via OhioLINK's ETD Center
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da, Silva Anderson Ramos. "Nuevos tensioactivos catiónicos basados en ramnolípidos y aminoácidos: propiedades fisicoquímicas y biológicas." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668100.
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La búsqueda de nuevos productos que sean multifuncionales, biocompatibles, biodegradables y que puedan alcanzar los objetivos económicos y ambientales establecidos en la actualidad se ha convertido en una cuestión no solo importante, sino que también esencial. Los avances recientes en la ciencia y la tecnología han otorgado a los biotensioactivos un papel más visible y predominante debido a que provienen de rutas de producción renovables basadas en microbios. De todas las variedades de microorganismos que producen estas sustancias, las especies del género Pseudomonas producen un tipo de glicolípidos típicamente llamados ramnolípidos (RLs). Recientemente, se están aplicando enfoques innovadores para mejorar la multifuncionalidad de estos ramnolípidos. El objetivo principal de esta memoria de tesis fue la modificación estructural de RLs convencionales para la obtención de RLs con carga positiva con el fin de conseguir nuevas moléculas que posean diferentes propiedades fisicoquímicas y biológicas de cara a ampliar el campo de aplicación de los precursores. Los resultados obtenidos indicaron que estos tensioactivos tienen la capacidad de formar agregados vesiculares a bajas concentraciones de estudio y son muy efectivos en reducir la tensión superficial del agua necesitando para ello poca cantidad de producto. Además, se observó que todos los tensioactivos obtenidos en este trabajo son fácilmente biodegradables en condiciones restrictivas, dando a entender que en el medio ambiente se degradarían con mayor facilidad. En esta memoria también se demostró que los nuevos ramnolípidos catiónicos derivados de arginina no solo presentan una actividad antimicrobiana a bajas concentraciones frente a los tres microorganismos representativos: bacterias, levaduras y protozoos, sino que también se observó que estos derivados consiguen desestructurar biofilms maduros de Candida spp. resistentes al fluconazol. Todos los ramnolípidos estudiados mostraron tener actividad antitumoral frente a líneas tumorales de mama, cuello uterino y piel. En general, son tensioactivos que presentan moderada citotoxicidad y actividad hemolítica. Se demostró que los ramnolípidos catiónicos derivados de lisina y arginina tienen la capacidad de compactar el ADN a bajas concentraciones y podrían ser estudiados como una alternativa futura para su aplicabilidad en el campo de la terapia génica. Como conclusión general, la combinación de un grupo de cabeza con carga positiva (aminoácidos) acoplada a los ramnolípidos (monoRL y Rlmezcla) permitieron la obtención de nuevos compuestos multifuncionales, de bajo coste económico, biocompatibles y biodegradables.The search for new multifunctional, biocompatible and biodegradable products that could reach economic and environmental goals became nowadays a concern not only important, but also essential. Advances in science and technology allowed biosurfactants became more visible in this field due to its renewable production by using specific microbes. The species belonging to the genus Pseudomonas are able to producing a kind of glycolipids typically called rhamnolipids (RLs). Recently, numerous innovative approaches are being applied in order to improve the multifunctionality of these RLs. The main objective of this thesis report was to perform a structural modification of the conventional RLs in order to achieve positively charged RLs with the purpose of not only obtaining new molecules that possess different physicochemical and biological properties but also expanding their applications. Results showed that these surfactants are able to form vesicular aggregates at low study concentrations and are very effective and efficient in reducing the surface tension of the water. It can also be observed that all the surfactants obtained in this thesis are easily biodegradable in restrictive conditions, which means that they would be degraded in an easier way in the environment. Besides, in this report it was shown that the RLs arginine conjugates exhibited antimicrobial activity at low concentrations against the three studied representative microorganisms: bacteria, yeasts and protozoa. These derivatives were also found to be capable of deconstructing mature biofilms of Candida spp. resistant to fluconazole. All the studied RLs showed antitumor activity against cancerous lines of breast, cervix and skin tumours. In general, the surfactants exhibited a moderate cytotoxicity and hemolytic activity. On the other hand, it was demonstrated that lysine and arginine-derived cationic RLs have the ability to compact DNA at low concentrations. As a general conclusion, the combination of a group of a positively charged amino acid head coupled with rhamnolipids (monoRL y Rlmezcla) resulted in obtaining new multifunctional compounds of low economical cost, biocompatibles and biodegradables.
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Gaudin, Théophile. "Développement de modèles QSPR pour la prédiction et la compréhension des propriétés amphiphiles des tensioactifs dérivés de sucre." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2318/document.
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Les tensioactifs dérivés de sucres représentent la principale famille de tensioactifs bio-sourcés et constituent de bons candidats pour substituer les tensioactifs dérivés du pétrole puisqu'ils sont issus de ressources renouvelables et peuvent être autant, voire plus performants dans diverses applications, comme la formulation (détergents, cosmétiques,…), la récupération assistée du pétrole ou des minéraux, etc. Différentes propriétés amphiphiles permettent de caractériser la performance des tensioactifs dans de telles applications, comme la concentration micellaire critique, la tension de surface à la concentration micellaire critique, l'efficience et le point de Krafft. Prédire ces propriétés serait bénéfique pour identifier plus rapidement les tensioactifs possédant les propriétés désirées. Les modèles QSPR sont des outils permettant de prédire de telles propriétés, mais aucun modèle QSPR fiable dédié à ces propriétés n'a été identifié pour les tensioactifs bio-sourcés, et en particulier les tensioactifs dérivés de sucres. Au cours de cette thèse, de tels modèles QSPR ont été développés. Une base de données fiables est nécessaire pour développer tout modèle QSPR. Concernant les tensioactifs dérivés de sucres, aucune base de données existante n'a été identifiée pour les propriétés ciblées. Cela a donné suite à la construction de la première base de données de propriétés amphiphiles de tensioactifs dérivés de sucres, qui est en cours de valorisation. L'analyse de cette base de données a mis en évidence différentes relations empiriques entre la structure de ces molécules et leurs propriétés amphiphiles, et permis d'isoler des jeux de données les plus fiables et au protocole le plus homogène possibles en vue du développement de modèles QSPR. Après établissement d'une stratégie robuste pour calculer les descripteurs moléculaires constituant les modèles QSPR, qui s'appuie notamment sur des analyses conformationnelles des tensioactifs dérivés de sucres et des descripteurs des têtes polaires et chaînes alkyles, différents modèles QSPR ont été développés, validés, et leur domaine d'applicabilité spécifié, pour la concentration micellaire critique, la tension de surface à la concentration micellaire critique, l'efficience et le point de Krafft. Pour les trois premières propriétés, des modèles quantitatifs performants ont pu être obtenus. Si les descripteurs quantiques ont apporté un gain prédictif important pour la tension de surface à la concentration micellaire critique, et un léger gain pour la concentration micellaire critique, aucun gain n'a été observé pour l'efficience. Pour ces trois propriétés, des modèles simples basés sur des descripteurs constitutionnels des parties hydrophile et hydrophobe de la molécule (comme des décomptes d'atomes) ont aussi été obtenus. Pour le point de Krafft, deux arbres de décision qualitatifs, classant la molécule comme soluble ou insoluble dans l'eau à température ambiante, ont été proposés. Les descripteurs quantiques ont ici aussi apporté un gain en prédictivité, même si un modèle relativement fiable basé sur des descripteurs constitutionnels des parties hydrophile et hydrophobe de la molécule a aussi été obtenu. Enfin, nous avons montré comment ces modèles QSPR peuvent être utilisés, pour prédire les propriétés de nouvelles molécules avant toute synthèse dans un contexte de screening, ou les propriétés manquantes de molécules existantes, et pour le design in silico de nouvelles molécules par combinaison de fragmentsSugar-based surfactants are the main family of bio-based surfactants and are good candidates as substitutes for petroleum-based surfactants, since they originate from renewable resources and can show as good as, or even better, performances in various applications, such as detergent and cosmetic formulation, enhanced oil or mineral recovery, etc. Different amphiphilic properties can characterize surfactant performance in such applications, like critical micelle concentration, surface tension at critical micelle concentration, efficiency and Kraft point. Predicting such properties would be beneficial to quickly identify surfactants that exhibit desired properties. QSPR models are tools to predict such properties, but no reliable QSPR model was identified for bio-based surfactants, and in particular sugar-based surfactants. During this thesis, such QSPR models were developed. A reliable database is required to develop any QSPR model. Regarding sugar-based surfactants, no database was identified for the targeted properties. This motivated the elaboration of the first database of amphiphilic properties of sugar-based surfactants. The analysis of this database highlighted various empirical relationships between the chemical structure of these molecules and their amphiphilic properties, and enabled to isolate the most reliable datasets with the most homogeneous possible protocol, to be used for the development of the QSPR models. After the development of a robust strategy to calculate molecular descriptors that constitute QSPR models, notably relying upon conformational analysis of sugar-based surfactants and descriptors calculated only for the polar heads and for the alkyl chains, different QSPR models were developed, validated, and their applicability domain defined, for the critical micelle concentration, the surface tension at critical micelle concentration, the efficiency and the Kraft point. For the three first properties, good quantitative models were obtained. If the quantum chemical descriptors brought a significant additional predictive power for the surface tension at critical micelle concentration, and a slight improvement for the critical micelle concentration, no gain was observed for efficiency. For these three properties, simple models based on constitutional descriptors of polar heads and alkyl chains of the molecule (like atomic counts) were also obtained. For the Krafft point, two qualitative decision trees, classifying the molecule as water soluble or insoluble at room temperature, were proposed. The use of quantum chemical descriptors brought an increase in predictive power for these decision trees, even if a quite reliable model only based on constitutional descriptors of polar heads and alkyl chains was also obtained. At last, we showed how these QSPR models can be used, to predict properties of new surfactants before synthesis in a context of computational screening, or missing properties of existing surfactants, and for the in silico design of new surfactants by combining different polar heads with different alkyl chain
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Lu, Huiling. "Contribution à l'étude des relations structure-propriétés de molécules amphiphiles à tête sucre." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2316/document.
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Dans le contexte du développement durable, l’'utilisation des ressources renouvelables, biodégradable et peu toxique, est particulièrement recherchée. En particulier, la littérature montre que les molécules amphiphiles biosourcées avec une tête sucre, type glycolipides, sont d'excellents candidats pour substituer les tensioactifs pétrochimiques actuellement utilisés massivement en formulation. Pour limiter le criblage expérimental et orienter le choix des synthèses de telles molécules, une démarche prédictive à partir de l'analyse de la structure moléculaire permettrait d'anticiper les propriétés des molécules amphiphiles et d'identifier celles répondant à des propriétés spécifiques recherchées. L'objectif des travaux de thèse est de développer une méthodologie via la synthèse à façon avec modification graduelle de la structure, la caractérisation et l'analyse systématique de glycolipides, dans le but d'identifier des liens pertinents entre leurs propriétés amphiphiles et leurs caractéristiques structurales. Les données expérimentales générées doivent permettent d'établir une base de données comparables et fiables, nécessaire pour le développement de modèles 1 prédictifs. Les résultats ont mis en évidence l'influence significative de certains paramètres de structure sur j les propriétés physico-chimiques, avec des tendances claires, autrement difficiles à observer à partir des données globales non-comparables de la littérature. Ce travail a également démontré l'importance de prendre en considération le comportement des molécules amphiphiles dans l'eau, via la connaissance de leur diagramme de phase, afin de définir sans ambiguïté certaines propriétés telles que la CMCIn the context of sustainable development, the use of biodegradable and low toxic renewable resources is particularly important. ln particular, the literature shows that the bio-based amphiphilic molecules with a sugar head, or the glycolipids, are excellent substitutes of the petrochemical surfactants used massively in current formulations. To limit the experimental screening and to orient the choice of the syntheses of such molecules, a predictive approach based on the analysis of the molecular structure would make it possible to anticipate the properties of the amphiphilic molecules and to identify those with specific properties. The objective of this work is to develop a methodology through systematic syntheses, characterizations and analyses of glycolipids with gradual structural modifications, with the aim of identifying relevant links between heir amphiphilic properties and their structural characteristics. The obtained experimental data should make it possible to establish a comparable and reliable database, necessary for the development of predictive models. The results showed the significant influence of some structural parameters on the physico-chemical properties with clear trends, which are otherwise difficult to observe by using the non-comparable data collected from the literature. This work also demonstrated the importance of considering the behavior of amphiphilic molecules in water, through knowledge of their phase diagram, which allows for the unambiguous definition of certain properties like the CMC
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Dussaussoy, Benjamin. "Application des tensioactifs biosourcés à la remédiation des sols pollués aux hydrocarbures." Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2605.
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La compréhension du transport et des interactions de tensioactifs biosourcés en milieu poreux présente un grand intérêt dans les applications environnementales, en particulier pour le contrôle du procédé de dépollution des sols par lavage. L’objectif de ces travaux de thèse est d’étudier le rôle de l’hétérogénéité physique et de l’hydrodynamique du milieu ainsi que de l’impact des propriétés des molécules tensioactives sur les mécanismes de transport et de rétention des tensioactifs dans les milieux poreux saturés en vue de leur dépollution. Une démarche de sélection progressive des produits a permis dans un premier temps une présélection des produits disponibles sur le marché (douze tensioactifs). Ceux-ci ont été analysés et caractérisés en laboratoire. Puis, des expériences de traçage et d’injection de solutions tensioactives ont été menées à l’échelle de colonnes de laboratoire dans deux milieux poreux aux propriétés distinctes et avec les trois tensioactifs ayant le meilleur potentiel pour l’application choisie. Ils ont été comparés au Triton X100, un tensioactif pétrosourcé, référence dans le domaine de la dépollution des sols.Afin de caractériser l’écoulement dans les milieux poreux, un soluté non-réactif a été utilisé comme traceur de l’eau. Des simulations numériques ont été réalisées en utilisant le code de calcul HYDRUS-1D afin de modéliser l’écoulement et d’estimer les paramètres de transport et de dépôt des tensioactifs. Ces résultats ont permis d’émettre des hypothèses sur les mécanismes d’interaction entre les tensioactifs, le polluant hydrophobe et le milieu poreux menant ainsi à une meilleure compréhension du procédé et à l’amélioration de son efficacitéUnderstanding transport and interactions of bio-based surfactants in porous medium is a main issue in environmental applications, in particular for the control of the soil washing remediation process. The objective of this work is to study the role of the physical heterogeneity and hydrodynamics of the medium as well as the impact of the properties of surfactant molecules on the mechanisms of transport and retention of surfactants in a saturated porous media,A progressive product selection process has allowed a preselection of the products available on the market (twelve surfactants). These were analyzed and characterized in the laboratory. Then, tracer experiments and injection of surfactant solutions were carried out at laboratory column scale with two porous media with distinct properties and using the three surfactants having the best potential for the soil washing application. They were compared to Triton XIOO, a petroleum-based surfactant, a reference in soil remediation field.In order to characterize the flow in porous media, a non-reactive solute was used as a water tracer. Numerical simulations were performed using the HYDRUS-ID code to model the flow and estimate the transport and deposition parameters of surfactants. These results made it possible to put forward hypotheses on the mechanisms of interaction between the surfactants, the hydrophobic pollutant and the porous medium, thus they lead to a better understanding o the process and to the improvement of its efficiency
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Christopher, Peter S. "Amphiphile mesostructures /." 2003. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3108069.
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Magwaza, Rachael Ntombikayise. "Synthesis and characterization of novel [Pt(diimine) (acylthiourea)]+ complexes as potential anticancer agents and exploring the use of sulphobutyl-ether-B-cyclodextrin and surfactant micelles as a drug delivery system." Thesis, 2017. https://hdl.handle.net/10539/24161.
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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirement for the degree Master of Science (MSc) in Chemistry. Johannesburg, March 2017.A series of [Pt(diimine)(Ln-O,S)]Cl complexes, where Ln-O,S represents a series of N,N dialkyl-N’-acylthiourea ligands and diimine represents (1,10-Phenanthroline; 5,6-dimethyl 1,10-phenanthroline or [3,2-d:2’,3’-f]-quinoxaline were successfully synthesised and characterised. A new crystal structure was obtained for N,N-di(2-hydroxy)-N’ benzoylthiourea which revealed an interesting herringbone crystal packing arrangement. The cytotoxicity of the series of complexes was evaluated on H1975 lung cancer cell lines at 50 µM and 5 µM. All the complexes were highly cytotoxic with cell death of 90-98% at 50 µM. However, at 5 µM there were much more variations on cell viability percentages. Although the structure–activity relationship can only be established when the IC50 (the concentration of an inhibitor where the response is reduced by half) values are determined, it is clear that the complexes containing the methyl substituents on the 5 and 6 positions of the phenanthroline moiety were the most cytotoxic with almost 98% cell death at 5 µM. The solubility of the complexes did improve by using N,N-dialkyl-N’-acylthiourea as ancillary ligands, however aqueous solubility remains a major problem. Sulphobutyl-ether-β-cyclodextrin (captisol) and low-molecular-weight surfactant micelles as drug delivery systems were considered in attempt to improve the solubility. DOSY NMR Spectroscopy revealed that there was no inclusion complex formation between the complex and capstiol, although the chemical shift trend suggested that there is at least some interaction. The low-molecular-weight surfactant micelles were considered as an alternative, which showed some promise as a drug delivery system, since the aqueous solubility improved and a colloidal suspension was obtained.
LG2018
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Court, Colin Edwin, University of Western Sydney, and of Science Technology and Environment College. "Surface properties of polymeric surfactants." 2001. http://handle.uws.edu.au:8081/1959.7/29518.
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Polystyrenes with carboxyl end-groups (PS-COOH)and poly (tert-butyl acrylates) (PtBA) of different molar mass were synthesised by anionic polymerisation using n-butyllithium as the initiator. Gel permeation chromatography (GPC) was used to calculate the molecular weight and polydispersity of these polymers. The tacticity of these polymers was determined using Carbon 13 Nuclear Magnetic Resonance Spectroscopy (13C NMR). FT-IR was used to confirm the tacticity of the samples. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF) was used to confirm the presence of the carboxyl end-groups. All of the films studied in this project were transferred to mica substrates using the Langmuir-Blodgett deposition method. Both single layer and multiple layer films were constructed using this technique. Atomic force microscopy (AFM) was used to observe the surface topology of these films.Doctor of Philosophy (PhD) (Science)
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Rutherford, Christine Elizabeth. "The destabilising effects of various cations on a surfactant derivative of poly iso-butenyl succinic anhydride." Thesis, 1990. http://hdl.handle.net/10413/7806.
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The interfacial behaviour of two amphiphillic poly iso-butenyl
succinic anhydride (PIBSA)-derived surfactants and the effect
of their interaction with various nitrate salts on the
stability of a water-in-oil type emulsion has been
investigated. The adsorption of the esterification product of PIBSA and
coco-diethanolamide (PICDEA) and of Experse-70 (E-70) at the
equilibrated aqueous-fuel oil interface was investigated via
the measurement of interfacial tension using the ring
detachment method.The interfacial pressure of PICDEA decreased in the presence
of excess unreacted coco-diethanolamide (CDE) and for both
PICDEA and E-70 interfacial pressure decreased with an
increase in the length of the poly iso-butenyl (PIB)
hydrocarbon tail. Interfacial tension-concentration curves and
the Gibbs Equation were used to determine surfactant surface
excess concentration and the packing efficiency of the
surfactant in the interphase. The double hydrocarbon PICDEA
molecule was found to occupy a larger interfacial area than
the single hydrocarbon E-70 molecule. The pH of the aqueous phase effects the interfacial activity
and nature of, PICDEA and E-70 at the interface. PICDEA is
protonated at pH values less than 4.6 and deprotonated at
higher pH values. E-70 is neutral at low pH and deprotonated
at pH values greater than approximately 2.The effect of sodium, calcium and ferric nitrate salts on the
interfacial free energy of the surfactant saturated interface
was also determined. The interfacial tension at the E-70
aqueous nitrate interface was dependent on ionic strength
alone with a general decrease in interfacial free energy as
nitrate concentration was increased. In the case of PICDEA,
however, a surfactant-cation orientation effect was observed.
The divalent Ca2+ cation attracts two adjacent PICDEA anions
resulting in the adverse interaction of hydrocarbon tails in
the interphase. This produces an interface with a higher than
expected interfacial free energy. The Na+ cation produces an
interface with a more energetically stable orientation.
PICDEA in the presence of a ferric nitrate solution (pH 1 to
2) is protonated and therefore the univalent nitrate anion
forms the counterion layer at the positively charged
surfactant interface. Stability studies were carried out on aqueous nitrate salt in
diesel emulsions using PICDEA as the stabilizing surfactant.
Droplet coalescence rates were determined from droplet size
distribution data in the presence of varying concentrations of
sodium, calcium and ferric nitrate salts. Droplets were sized
microscopically at progressive time intervals and the rate of
coalescence determined from the change in droplet
concentration with time. Coalescence was found to follow two or more consecutive first
order reactions. After an initial period of rapid droplet
coalescence, involving small droplets with diameters of 5~m
and less, a droplet distribution is attained conducive to a
more stable emulsion which then undergoes a slower rate of
coalescence involving larger droplets.
The effect of the nitrate salt type on the initial droplet
coalescence rate (in order of increasing rate) is as follows:
Ca2+< Na+< Fe3+. The opposite trend was observed for the
slower long term rate of coalescence, i.e. Fe3+< Na+< Ca2+.
These trends are explained in terms of the surfactant cation
orientation effect, the effect of the droplet's radius of
curvature on the potential energy barrier against coalescence
and the effect of the droplet distribution of the emulsion
system.Thesis (M.Sc.)-University of Natal, Durban, 1990.
31
Ganesh, A. V. "Formation Of Cream In Emulsions." Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1666.
Full text
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Pavlovich, James Gilbert. "Ion pairing of nucleotides with surfactants for enhanced sensitivity in liquid matrix assisted secondary ion mass spectrometry." Thesis, 1993. http://hdl.handle.net/1957/36760.
Full textAbstract:
In particle induced desorption-ionization mass spectrometry the strength of an
analyte's signal under a given set of bombardment conditions is usually considered to
be representative of the analytes relative surface activity. This rationale is generally
used to explain differences in the technique's sensitivity between and within various
classes of compound. In liquid matrix assisted secondary ion mass spectrometry
(SIMS) sensitivity enhancement of ionic analytes by pairing with surface active
counterions has been demonstrated by several groups. This technique has been utilized
in this work to achieve a 10,000 fold enhancement in the signal for ATP on a double
focusing magnetic sector instrument and to detect femtomole quantities of nucleoside
monophosphates on a time-of-flight instrument. The analyte's signal, however, is
dependent on both the analyte bulk concentration and that of the surfactant.
Additionally, the surfactant concentration that produces the maximum analyte signal
changes with the analyte concentration. In this study, this phenomenon has been
modeled in terms of conventional solution equilibria and surface chemical principles.
It is assumed that the initial surface composition and the bulk concentration are the
boundary conditions of a steady state established by the competing processes of surface
sputtering and surface replenishment from the bulk during analysis. Calculated surface
excesses correlate well with observed relative ion intensities, suggesting that equilibrium
conditions are approached in the sample matrices despite the outwardly dynamic nature
of the sputtering processes.Graduation date: 1994
33
"The influence of surfactants on the solubility of acenaphthene and phenanthrene and their extraction from spiked soils." Thesis, 2005. http://hdl.handle.net/10413/1887.
Full textAbstract:
In the first phase of the study, the effect of five Safol surfactants on the aqueous solubility of phenanthrene and acenaphthene was determined. The fixed variables were temperature and ionic strength, while surfactant concentration and pH were varied. Quantification of the polyaromatic hydrocarbons (PAHs) was conducted by UV-Visible spectrophotometry. The surfactants had little or no effect on analyte solubilisation below the critical micelle concentration (CMC) while a linear relationship between surfactant concentration and amount of solubilised phenanthrene was observed above CMC concentrations. Safol 45E5 had the highest phenanthrene molar solubilisation ratio (0.83) of the five surfactants tested. The solubilisation of phenanthrene increased marginally (4.1 % for Safol 45E12 and 15.2 % for Safol 45E7) by decreasing the pH from 8 to 5. The concentration of solubilised acenaphthene was 8.4 % higher than phenanthrene in a 1 mM solution of Safol 45E7. The aqueous solubility of phenanthrene was enhanced 11.0, 21.2, 19.6, 15.9 and 14.7 times in 1 mM solutions of Safol 45E3, 45E5, 45E7, 45E9 and 45E12 respectively. Seasand, Longlands sand, Longlands soil and a standard soil sample were spiked with the two PAHs and aged for two weeks. API sludge provided by Sasol and unspiked samples of the above mentioned sorbents were subjected to determinations of organic matter content, particle size distribution and moisture content. The spiked soils and sands and the sludge samples were then washed in various concentrations of Safol 45E7 (0.5, 1.0 and 2.0 mM) at the same temperature used in the solubility studies. A soil mass to solution volume of lg to 10 mL was used. Analyses of the soil and sand samples were conducted by High Pressure Liquid Chromatography (HPLC). Using a 2 mM Safol 45E7 surfactant solution, 100 % and 90 % of phenanthrene and acenaphthene were respectively extracted from Longlands sand and 88 % and 100 % of phenanthrene and acenaphthene were removed from seasand. 8.4 % phenanthrene and 8.17 % of acenaphthene was removed from Longlands soil, while 7.03 % phenanthrene and 6.64 % acenaphthene was removed from the standard soil sample. In the sand desorption studies, the amount of desorbed contaminants initially increased rapidly with increasing surfactant concentration, before levelling off at equilibrium. The amount of desorbed acenaphthene and phenanthrene increased exponentially with increasing surfactant concentration while contaminant concentrations decreased with increasing time in the Longlands soil and standard soil desorption experiments. Dry API sludge samples were also subjected to soil washing studies. The washed samples were Soxhlet extracted and analysed by gas chromatography. The 0.5 mM and 1 mM Safol 45E7 washed sludge samples showed respective phenanthrene peak area percent reductions representing a 44 % and 47 % extraction of phenanthrene from the API sludge.Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
34
Kim, Derek Doowon. "Structure and Property Correlations of Surface-Active Agents in the Control of Colloidal Behavior in Home/Personal Care and Biochemical Systems." Thesis, 2021. https://doi.org/10.7916/d8-7v0p-yh46.
Full textAbstract:
Complexity in Home and Personal Care appears in several forms – the product, the substrate, and their interactions. The aim of this thesis is to investigate strategies for selecting effective surface-active agents (surfactants) that can be used in combination with other active ingredients in industry-relevant formulations deployed in the personal care sector. This thesis is composed of three parts, each of which involves a study of a complex natural system as it is affected by the addition of a complex chemical mixture. This is done in an effort to expose key features of the design rules for engineering the chemical mixture to enhance baseline performance via synergistic interactions of the formulation components and the natural system components.
The first topic is an investigation on how the effectiveness of surface-active agents for removing a mixture of hydrophobic and hydrophilic soils from fabrics is related to the surfactants' physical-chemical features. The second topic is an exploration of compatible surfactant-enzyme systems that can be used in various industrial applications, where the behavior at a variety of interfaces is concomitantly important. Here, the focus is on the effect of surfactant structure and properties on enzyme function (i.e., activity), structural mobility and stability. The third topic is an investigation on the usefulness of micro-Raman spectroscopy for determining in situ chemical information that relates to the effects of a variety of surfactants on the mechanical and textural features of skin.
35
Grant, Colin A., Peter C. Twigg, G. Bell, and J. R. Lu. "AFM relative stiffness measurement of the plasticising effect of a non-ionic surfactant on plant leaf wax." 2008. http://hdl.handle.net/10454/5994.
Full textAbstract:
An AFM relative stiffness technique was applied to reconstituted Beta vulgaris L. wax films. Consecutive force arrays (n=100) made on the waxy surface at the same locations showed that there was no relative change in surface elasticity and this information was used as a reference to further experimental measurements. A surfactant solution was subsequently dropped on the waxy surface and the same array of indents was made at the same location as the reference test. The plant wax surface showed a reduction in its surface elasticity properties. The study has demonstrated that the AFM technique could be used to undertake a systematic assessment of the plasticising effects of agrochemicals on native and reconstituted plant wax films.
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Lee, Hyo Jin. "Molecular origins of surfactant-mediated stabilization of protein." Thesis, 2012. http://hdl.handle.net/1957/33834.
Full textAbstract:
Nonionic surfactants are commonly used to stabilize proteins during upstream and downstream processing and drug formulation. Surfactants stabilize the proteins through two major mechanisms: (i) their preferential location at nearby interfaces, in this way precluding protein adsorption; and/or (ii) their association with protein into "complexes" that prevent proteins from interacting with surfaces as well as each other. In general, both mechanisms must be at play for effective protein stabilization against aggregation and activity loss, but selection of surfactants for protein stabilization currently is not made with benefit of any quantitative, predictive information to ensure that this requirement is met.
In certain circumstances the kinetics of surface tension depression (by surfactant) in protein-surfactant mixtures has been observed to be greater than that recorded for surfactant alone at the same concentration. We compared surface tension depression by poloxamer 188 (Pluronic�� F68), polysorbate 80 (PS 80), and polysorbate 20 (PS 20) in the presence and absence of lysozyme and recombinant protein, at different surfactant concentrations and temperatures. The kinetic results were interpreted with reference to a mechanism for surfactant adsorption governed by the formation of a rate-limiting structural intermediate (i.e., an "activated complex") comprised of surfactant aggregates and protein. The presence of lysozyme was seen to increase the rate of surfactant adsorption in relation to surfactant acting alone at the same concentrations for the polysorbates while less of an effect was seen for Pluronic�� F68. However, the addition of salt was observed to accelerate the surface tension depression of Pluronic�� F68 in the presence of lysozyme. The addition of a more hydrophobic, surface active protein (Amgen recombinant protein) in place of lysozyme resulted in greater enhancement of surfactant adsorption than that recorded in the presence of lysozyme. A simple thermodynamic analysis indicated the presence of protein caused a reduction in ���G for the surfactant adsorption process, with this reduction deriving entirely from a reduction in ���H. We suggest that protein accelerates the adsorption of these surfactants by disrupting their self associations, increasing the concentration of surfactant monomers near the interface.
Based on these air-water tensiometry results, it is fair to expect that accelerated surfactant adsorption in the presence of protein (observed with PS 20 and PS 80) will occur with surfactants that stabilize protein mainly by their own adsorption at interfaces, and that the absence of accelerated surfactant adsorption (observed with F68) will be observed with surfactants that form stable surfactant-protein associations. Optical waveguide lightmode spectroscopy was used to test this expectation. Adsorption kinetics were recorded for surfactants (PS 20, PS 80, or F68) and protein (lysozyme or Amgen recombinant protein) at a hydrophilic solid (SiO���-TiO���) surface. Experiments were performed in sequential and competitive adsorption modes, enabling the adsorption kinetic patterns to be interpreted in a fashion revealing the dominant mode of surfactant-mediated stabilization of protein in each case. Kinetic results confirmed predictions based on our earlier quantitative analysis of protein effects on surface tension depression by surfactants. In particular, PS 20 and PS 80 are able to inhibit protein adsorption only by their preferential location at the interface, and not by formation of less surface active, protein-surfactant complexes. On the other hand, F68 is able to inhibit protein adsorption by formation of protein-surfactant complexes, and not by its preferential location at the interface.Graduation date: 2013
Access restricted to the OSU Community at author's request from Sept. 24, 2012 - Feb. 24, 2013.
37
Feldmann, Jeanna Marie. "Discrimination of color copier/laser printer toners by Raman spectroscopy and subsequent chemometric analysis." 2013. http://hdl.handle.net/1805/3693.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)Toner analysis has become an area of increased interest due to the wide availability of laser printers and photocopiers. Toner is most often encountered on paper in questioned document analysis. Because of this, it is important to develop methods that limit the interference of paper without damaging or destroying the document. Previous research using Fourier transform infrared spectroscopy (FTIR) has differentiated toners based on their polymer resin components. However, Raman spectroscopy and chemometric analysis are not typically used for the examination of this material. Raman spectroscopy is a popular tool for the chemical analysis of pigmented samples and was used to characterize cyan, yellow, and magenta toners. Analyses were performed using a dispersive micro-Raman spectrometer equipped with a 785nm diode laser, a CCD detector, and an objective at 20X magnification. One hundred samples of each color toner were collected. Three different and separate methods were developed for cyan, yellow, and magenta toners on paper to optimize results. Further analysis of the magenta toners was excluded due to a weak signal and significant paper interference. The data collected from the analyses of the blue and yellow toners was then processed using a combination of statistical procedures, including principal component analysis (PCA), agglomerative hierarchal clustering (AHC), and discriminative analysis (DA). Ninety-six blue toners were analyzed by PCA and three classes of spectra were suggested. Discriminant analysis showed that the three classes were well-differentiated with a cross-validation accuracy of 100% for the training set and 100% cross-validation accuracy for the external validation set. Eighty-eight yellow toners were analyzed by AHC and four classes of spectra were suggested. Discriminant analysis showed good differentiation between the classes with a cross-validation accuracy of 95.45% for the training set, but showed poor differentiation for the external validation set with a cross-validation accuracy of 72%. While these toners were able to be discriminated, no correlation could be made between the manufacturer, printer make and model, and the toner sample.
38
Place, Benjamin J. "Analytical method development for the identification, detection, and quantification of emerging environmental contaminants in complex matrices." Thesis, 2012. http://hdl.handle.net/1957/32606.
Full textAbstract:
The development of analytical methods for emerging contaminants creates many unique challenges for analytical chemists. By their nature, emerging contaminants have inherent data gaps related to their environmental occurrence, fate, and impact. This dissertation is a compilation of three studies related to method development for the structural identification of emerging contaminants, the detection and quantification of chemicals used in unprecedented quantities and applications, and the extraction of compounds from complex matrices where the solvent-solute-matrix interactions are not completely understood. The three studies present analytical methods developed for emerging contaminants in complex matrices, including: fluorochemical surfactants in aqueous film-forming foams, oil dispersant surfactants in seawater, and fullerene nanomaterials in carbonaceous solids.
Aqueous film-forming foams, used in military and commercial firefighting, represent environmentally-relevant commercial mixtures that contain a variety of fluorochemical surfactants. Combining the surfactant-selective ionization of fast atom bombardment mass spectrometry with high resolution mass spectrometry, chemical formulas for 11 different fluorochemical classes were identified. Then AFFF-related patents were used to determine the structures. Of the eleven classes of fluorochemicals, ten have little, if any, data on their environmental occurrence, fate, and potential impacts in the peer-reviewed literature. In addition, nine of the identified classes had either cationic or zwitterionic functionalities and are likely to have different transport properties compared to the well-studied anionic fluorochemicals, such as perfluorooctanoate.
After the Deepwater Horizon oil spill in the summer of 2010, one of the emergency response methods for the mitigation of the oil's environmental impact was the use of unprecedented amounts of oil dispersant to break down the oil slick and encourage biodegradation. This event illustrated the need for rapid analytical method development in order to respond to the potential environmental disaster in a timely manner. Using large volume injection liquid chromatography with tandem mass spectrometry, an analytical method was developed for the trace analysis of the multiple dispersant surfactant classes and the potential degradation products of the primary surfactant. Limits of detection ranged from 49 ��� 3,000 ng/L. The method provided excellent recovery (86 ��� 119%) and precision (10 ��� 23% RSD), while also accommodating for the high salinity of seawater samples and analyte contamination.
Despite the fact that fullerene nanomaterials have been studied for almost three decades, research is still being conducted to fully understand the environmental properties of these materials. Previous studies to extract fullerenes from environmental matrices have resulted in low efficiency, high variability, or the extraction efficiencies have gone unreported. Extraction by ultrasonication with toluene and 1-methylnaphthalene increased the recovery 5-fold of a spiked, isotopically-labeled C������ surrogate from carbon lampblack as compared to that of the conventional approach of extracting with 100% toluene. The study revealed the importance of evaluating experimental variables such as extraction solvent composition and volume, and sample mass, as they have a significant impact on the quantitative extraction of fullerenes from environmental matrices.Graduation date: 2013
Access restricted to the OSU Community at author's request from Aug. 15, 2012 - Aug. 15, 2013
39
Patil, S. S., E. Venugopal, S. Bhat, K. R. Mahadik, and Anant R. Paradkar. "Microstructural elucidation of self-emulsifying system: effect of chemical structure." 2012. http://hdl.handle.net/10454/6124.
Full textAbstract:
PURPOSE: Self-emulsifying systems (SES) emulsify spontaneously to produce fine oil-in-water emulsion when introduced into aqueous phase. The self-emulsification process plays an important role during formation of emulsion. The objective of current work was to understand and explore the inner structuration of SES through controlled hydration and further to study the influence of additive on the same which ultimately governs performance of final formulation in terms of droplet size. METHODS: Droplet size of final formulations containing structural analogues of ibuprofen was determined. Microstructural properties of intermediate hydrated regimes of SES were investigated using techniques such as small angle X-ray scattering, differential scanning calorimetry and rheology. RESULTS: The current work established inverse relationship between droplet size of the formulations containing structural analogues of ibuprofen and their Log P values. Microstructural analysis of intermediate hydrated regimes of the prepared samples showed formation of local lamellar structure. Structural analogues of ibuprofen significantly altered microstructure of lamellae which was well correlated with the droplet size of final formulations. In vitro drug release study showed increase in dissolution rate of lipophillic drugs when formulated as SES. CONCLUSION: The current work emphasizes the fact that tailor-made formulations can be prepared by controlling the properties of intermediate regimes.