Relevant bibliographies by topics / Cationic-anionic complexes

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers
  5. Reports

Academic literature on the topic 'Cationic-anionic complexes'

Author: Grafiati
Published: 5 June 2025
Last updated: 24 June 2025

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Journal articles on the topic "Cationic-anionic complexes"

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KD, Mack, Walzem RL, K. Lehmann‐Bruinsma, Powell JS, and Zeldis JB. "Polylysine enhances cationic liposome‐mediated transfection of the hepatoblastoma cell line Hep G2." Biotechnology and Applied Biochemistry 23, no. 3 (1996): 217–20. http://dx.doi.org/10.1111/j.1470-8744.1996.tb00378.x.

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Plasmid DNA condensed by polylysine enhanced cationic‐liposome‐mediated transfection of Hep G2 cells. The luciferase expression plasmid pCMVL was complexed with the polycation poly‐L‐lysine and mixed with liposomes that contained a 1:1 molar ratio of the cationic lipid 1,2‐dioleoyloxy‐3‐trimethyl‐ammoniumpropane, with the neutral phospholipid 1,2‐di‐(cis‐9‐octadecenoyl)‐sn‐glycero‐3‐phosphoethanolamine. Polylysine enhanced cationic‐liposome‐mediated transfection of the hepatoblastoma cell line Hep G2 9‐fold compared with pCMVL complexed alone with liposomes. The ratio of cationic to anionic charge of the polylysine‐pCMVL complexes, and the quantity of cationic liposomes, are important determinants for optimal transfection of Hep G2 cells.
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Ohtsuka, Yoshikazu, Toshio Naito, and Tamotsu Inabe. "Phthalocyanine-phthalocyanine salt crystal: a unique assembly design." Journal of Porphyrins and Phthalocyanines 09, no. 01 (2005): 68–71. http://dx.doi.org/10.1142/s1088424605000125.

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A unique salt composed of cationic and anionic phthalocyanine complexes has been prepared and structurally characterized. The cationic component is di(pyridine)(phthalocyaninato)cobalt(III) and the anionic one is dicyano(phthalocyaninato)cobalt(III). They arrange alternately in the crystal, forming a two-dimensional sheet with partial π–π overlaps.
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Guo, Pingxia, Qun He, Chen Wang, Zaili Hou, Bingran Yu, and Weifeng Bu. "Intensely phosphorescent block copolymer micelles containing gold(i) complexes." Soft Matter 14, no. 18 (2018): 3521–27. http://dx.doi.org/10.1039/c8sm00314a.

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Micellization of anionic block copolymers with cationic gold(i) complexes induces remarkable phosphorescence enhancement in solution. The extent of the luminescence enhancement increases with increasing molecular weight of the anionic block.
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Brewer, Ashley, Matthew Lacey, John R. Owen, Iris Nandhakumar, and Eugen Stulz. "Supramolecular hetero-porphyrin SWNT complexes." Journal of Porphyrins and Phthalocyanines 15, no. 04 (2011): 257–63. http://dx.doi.org/10.1142/s1088424611003227.

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The complexation of single walled carbon nanotubes (SWNTs) with neutral, anionic and cationic porphyrins has been investigated under identical complex forming conditions. The determination of the porphyrin loading reveals large differences depending on the nature of the porphyrin used. Combinations of different porphyrins to form mixed hetero-porphyrin complexes shows that the mixture of a cationic and anionic porphyrin results in loading which is an order of magnitude larger than in all other complexes. This complex also exhibits high adsorption and emission intensities and can be regarded as an extended co-operative binary ionic (CBI) solid. The complexes were further studied using Raman spectroscopy, elemental analysis, AFM and cyclic voltammetry.
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Vimala, B., S. R. Jayapradha, and A. Selvan. "Template Synthesis, Characterization and Reactivities of Anionic Transition Metal Complexes with Tetraaza Protonated 11,13-Dimethyl-1,4,7,10- tetraazacyclotrideca-4,6,10,13-tetraene-5,6-Diol as Cation." Asian Journal of Chemistry 31, no. 12 (2019): 2924–30. http://dx.doi.org/10.14233/ajchem.2019.22310.

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Template synthesis, characterization and reactivities of anionic transition metal complexes with tetraazaprotonated 11,13-dimethyl-1,4,7,10-tetraazacyclotrideca-4,6,10,13-tetraene-5,6-diol as cation has been achieved. By magnetic and spectral studies, hexachlorometallate(II) anionic complexes have been found to be octahedral. It is envisioned that the cationic macrocycle may be associating with both the complex and chloride anions through hydrogen bonding thereby rendering the molecule as a whole neutral. Deprotonation, protonation analysis and chemosensor behaviour have been showed by pH variation studies and relevant anionic additions, respectively. All of these data supports the newly synthesized anionic complexes in a strange manner.
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Pulletikurthi, Giridhar, Maryam Shapouri Ghazvini, Tong Cui, et al. "Electrodeposition of zinc nanoplates from an ionic liquid composed of 1-butylpyrrolidine and ZnCl2: electrochemical, in situ AFM and spectroscopic studies." Dalton Transactions 46, no. 2 (2017): 455–64. http://dx.doi.org/10.1039/c6dt04149c.

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Rajkumar, Eswaran, Paulpandian Muthu Mareeswaran, and Seenivasan Rajagopal. "Photophysical properties of amphiphilic ruthenium(ii) complexes in micelles." Photochem. Photobiol. Sci. 13, no. 9 (2014): 1261–69. http://dx.doi.org/10.1039/c4pp00043a.

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Liu, Zhen, Giridhar Pulletikurthi, Abhishek Lahiri, Tong Cui, and Frank Endres. "Suppressing the dendritic growth of zinc in an ionic liquid containing cationic and anionic zinc complexes for battery applications." Dalton Transactions 45, no. 19 (2016): 8089–98. http://dx.doi.org/10.1039/c6dt00969g.

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Gauthier, V. J., and M. Mannik. "Only the initial binding of cationic immune complexes to glomerular anionic sites is mediated by charge-charge interactions." Journal of Immunology 136, no. 9 (1986): 3266–71. http://dx.doi.org/10.4049/jimmunol.136.9.3266.

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Abstract The role of charge-charge interactions between cationic immune complexes and the anionic sites on the glomerular basement membrane was examined. For this purpose, soluble immune complexes at fivefold antigen excess were prepared with human serum albumin and cationized rabbit antibodies to this protein. When unrelated cationic proteins, protamine sulfate or cationized rabbit serum albumin, were given 1 min before the cationized immune complexes, glomerular immune deposits did not form. Cationic immune complexes allowed to deposit in glomeruli could readily be displaced by protamine sulfate or cationized rabbit serum albumin injected 1 min after the immune complexes. If the same cationic molecules were injected 1 hr after the immune complexes, the complexes could not be displaced from glomeruli. In contrast, cationic complexes that were deposited in glomeruli in the presence of a very high degree of antigen excess in circulation to prevent their condensation into larger complexes in glomeruli were readily displaced at 1 min and 1 hr with protamine sulfate or with cationized rabbit serum albumin. On the basis of these results, we concluded that the initial binding of cationic immune complexes to glomeruli occurs by charge-charge interactions. Once the immune complexes in glomeruli condense to larger deposits, forces other than charge-charge interactions are responsible for their retention in glomeruli.
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Mandai, Toshihiko, Hyuma Masu, and Patrik Johansson. "Extraordinary aluminum coordination in a novel homometallic double complex salt." Dalton Transactions 44, no. 25 (2015): 11259–63. http://dx.doi.org/10.1039/c5dt01220a.

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Dissertations / Theses on the topic "Cationic-anionic complexes"

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Hsu, Wei-Hsin. "Mixed anionic and cationic polyphosphazene complexes for effective gene delivery to glioblastoma in vitro and in vivo." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53452/.

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Gene delivery vectors that are safe, efficient and affordable could significantly enhance the prospects for genetic-based therapies. Here we describe an approach to such vectors, using new variants of polyphosphazene materials and describe the synthesis of a series of degradable polyphosphazenes with both cationic and anionic side-chains, and report their use as mixed polyelectrolyte complexes for DNA and RNA delivery to glioblastoma cells in vitro and in vivo. Precursor poly(allylamino-phosphazene)s were converted to cationic and anionic derivatives via a,w-thiolated alkylamines and alkylcarboxylates, respectively. Simultaneous co-incubation of alkylamine- and alkylcarboxylate-poly(phosphazenes) with nucleic acids generated polyelectrolyte complexes which were more compact than poly(alkylamino-phosphazene):DNA analogues but with similar positive surface charges. Screening of a series of these complexes for transfection of U87MG glioblastoma cells, showed that 6-mercaptohexanoic acid substituted poly(phosphazene)s mixed in the polycation/DNA complexes resulted in the highest luciferase expression in the cells. These data were consistent with an increased buffering capability of the 6-mercaptohexanoic acid substituted polymer across the early endosomal pH range in comparison with other anionic side-chain substituted polymers. Transfection assays in 3D spheroid models and in subcutaneous xenograft U87MG tumours confirmed higher transgene expression for these mixed cationic and anionic poly(phosphazene)s compared to the related poly(alkylamino-phosphazene)-DNA complexes, and also to PEI-DNA complexes. Extension of the approach to siRNA delivery showed that the mixed cationic and anionic poly(phosphazene)s were able to silence a gene encoding for a kinase implicated in tumour progression (DYRK1A), resulting in a reduced renewal ability of U87MG cells in vitro and in delay of tumour growth in a xenograft model.
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Kudaibergenov, S., K. Abdullin, A. Seitov, G. Tatykhanova, and Z. Sadakbayeva. "Preparation and characterization of thin films derived from polyelectrolyte-surfactant complexes based on cationic polymer - JR-400 and anionic surfactant - sodium dodecylbenzenesulfonate." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20970.

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Thomas, Fabien. "Mécanismes de rétention à l'interface alumine-solution aqueuse." Nancy 1, 1987. http://www.theses.fr/1987NAN10444.

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Le mécanisme d'adsorption à l'interface alimine-solution aqueuse a été étudié dans le cas de tensioactifs anioniques (alkylbenzènesulfonate de sodium) et de tensioactifs cationiques (chlorure d'alkyldiméthylbenzyl ammonium). Les propriétés structurales, texturales, superficielles des adsorbants ainsi que les propriétés électrochimiques ont été déterminées
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Chiu, Hsueh-Chen, and 丘學承. "Cationic dendrimer-DNA complexes：the effect of free polycations and anionic coating on the structure and cytotoxicity of the complexes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/62719452164357447542.

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碩士<br>嘉南藥理科技大學<br>藥物科技研究所<br>98<br>Cationic polymers used for gene delivery vectors were known to induce some severe adverse effects such as cytotoxicity by its excess cationic charge. The removal of free polycations would be desirable for the development of safe gene delivery systems. Also, recharging cationic DNA complexes with anionic coating has been reported to enhance the transfection performance and reduce cytotoxicity of DNA complexes. Therefore, the purpose of this study was to investigate the effect of free polycatons and anionic coating on the structure and cytotoxicity of polyamidoamine (PAMAM)/DNA complexes. In our study, free polycations are removed from the solutions of PAMAM/DNA complexes by filtration, and the resulting complexes were then coated with various anionic substances such as alginate, pectin, hyaluronic acid (HA), and bovine serum albumin (BSA). The structural properties were confirmed using particle size, zeta potential, and cytotoxic assay. Anionic coatings with polysaccharides and BSA resulted in the increases of particle size of PAMAM/DNA complexes and were shown as negative zeta potentials. Coatings with pectin and alginate resulted in the decreases of cytotoxicity in Raw 264.7 cells treated with PAMAM/DNA complexes and pectin had better protective effects on cell viability than alginate. The average particle size for PAMAM/DNA complexes without removal of excess polycations is significantly larger than that with removal of excess polycations by centrifugation. The cytotoxicity of PAMAM/DNA complexes is reduced with removal of excess polycations. After removing excess polycations, the average particle size for PAMAM/DNA complexes is increased by anionic coating with alginate, hyaluronic acid, bovine serum albumin, and pectin. Except BSA, the zeta potential of the complexes changed from positive values to negative ones by the increases of anionic concentrations. The results suggested that anionic coating of PAMAM/DNA complexes with various functional materials deserved to be further developed to optimize the performance of dendrimer-based gene delivery systems.
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Book chapters on the topic "Cationic-anionic complexes"

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Goddard, E. D., and P. S. Leung. "Complexes of Cationic Polymers and Anionic Surfactants." In Microdomains in Polymer Solutions. Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2123-1_23.

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Gresh, Nohad, Martin Leboeuf, and Dennis Salahub. "Energetics and Structure in Model Neutral, Anionic, and Cationic Hydrogen-Bonded Complexes." In ACS Symposium Series. American Chemical Society, 1994. http://dx.doi.org/10.1021/bk-1994-0569.ch006.

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Amiel, C., C. Galant, and L. Auvray. "Ternary complexes involving a β-cyclodextrin polymer, a cationic surfactant and an anionic polymer." In Trends in Colloid and Interface Science XVII. Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/b93967.

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Mehreteab, Ammanuel. "Effects of Structure on the Properties of Pseudononionic Complexes of Anionic and Cationic Surfactants." In Mixed Surfactant Systems. American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0501.ch028.

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Bochmann, Manfred. "Allyl and dienyl complexes." In Organometallics 2. Oxford University Press, 1994. http://dx.doi.org/10.1093/hesc/9780198558132.003.0005.

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This chapter focuses on allyl and dienyl complexes. The allyl ligand is the simplest in a series of non-cyclic conjugated anionic (enyl) ligands. Coordinated allyl is susceptible to nucleophilic attack—a property which has made allyl complexes invaluable in synthesis and is the basis of numerous catalytic reactions. The site of nucleophilic attack depends on the nature of the metal: allyl groups with cationic character are attacked in the 1,3-position, while anionic allyls react in the 2-position. The chapter then looks at the synthesis and reactivity of allyl complexes, before studying enyl complexes. Dienyl complexes, particularly iron tricarbonyl compounds, have important applications in stereoselective synthesis.
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Ojima, I., A. T. Vu, and D. Bonafoux. "Homoleptic, Cationic Norbornadiene Complexes via Anionic Ligand Abstraction." In Compounds with Transition Metal-Carbon pi-Bonds and Compounds of Groups 10-8 (Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os). Georg Thieme Verlag KG, 2001. http://dx.doi.org/10.1055/sos-sd-001-00447.

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Prado, Héctor J., María C. Matulewicz, and Marina Ciancia. "Naturally and Chemically Sulfated Polysaccharides in Drug Delivery Systems." In Advanced Pharmacy. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815049428123010009.

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Sulfated polysaccharides have always attracted much attention in food, cosmetic and pharmaceutical industries. These polysaccharides can be obtained from natural sources such as seaweeds (agarans, carrageenans, fucoidans, mannans and ulvans), or animal tissues (glucosaminoglycans). In the last few years, several neutral or cationic polysaccharides have been sulfated by chemical methods and anionic or amphoteric derivatives were obtained, respectively, for drug delivery and other biomedical applications. An important characteristic of sulfated polysaccharides in this field is that they can associate with cationic drugs generating polyelectrolyte-drug complexes, or with cationic polymers to form interpolyelectrolyte complexes, with hydrogel properties that expand even more their applications. The aims of this chapter are to present the structural characteristics of these polysaccharides, to describe the methods of sulfation applied and to review extensively and discuss developments in their use or their role in interpolyelectrolyte complexes in drug delivery platforms. A variety of pharmaceutical dosage forms which were developed and administered by multiple routes (oral, transdermal, ophthalmic, and pulmonary, among others) to treat diverse pathologies were considered. Different IPECs were formed employing these sulfated polysaccharides as the anionic component. The most widely investigated is κ-carrageenan. Chitosan is usually employed as a cationic polyelectrolyte, with a variety of sulfated polysaccharides, besides the applications of chemically sulfated chitosan. Although chemical sulfation is often carried out in neutral polysaccharides and, to a less extent, in cationic ones, examples of oversulfation of naturally sulfated fucoidan have been found which improve its drug binding capacity and biological properties.
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Ojima, I., A. T. Vu, and D. Bonafoux. "Homoleptic Cationic Cycloocta-1,5-diene Complexes via Anionic Ligand Abstraction." In Compounds with Transition Metal-Carbon pi-Bonds and Compounds of Groups 10-8 (Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os). Georg Thieme Verlag KG, 2001. http://dx.doi.org/10.1055/sos-sd-001-00442.

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Gamoudi, Safa, and Ezzeddine Srasra. "Modification of Clay Minerals by Surfactant Agents: Structure, Properties, and New Applications." In Surfactants - Fundamental Concepts and Emerging Perspectives [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.110317.

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Organically surfactant-modified clays (OC) have attracted a great deal of interest because of their wide applications in industry and environmental protection. The OC are organic–inorganic complexes synthesized through the intercalation of organic cations mainly into the interlayer space of expandable clays. Different surfactants have been used to prepare OC. These include single and dual-cationic surfactants, anionic–cationic surfactants, and nonionic surfactants. The intercalation of the surfactant cations was governed by different processes: cationic exchange and Van der Waals ‘interactions of the alkyl chains with clay surface. The structure and properties of the resultant organoclays are affected by the type of surfactant, the clay used, and the preparation method such as the conventional technique, the solid-state intercalation, and the microwave irradiation. As the result, the organoclays are characterized by hydrophobic surfaces and have attracted great interest because of their potential use in several applications, such as sorbents for organic pollutants (dyes, pharmaceutic compounds…), heavy metals and inorganic oxy-anions, clay-based nanocomposites, and in several other industries.
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Gazal, Umaima. "Applications of Ionic Liquids in Gas Chromatography." In Ionic Liquids - Thermophysical Properties and Applications [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96702.

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The environment offers an enormous innovative panorama of prospects intended for the research of novel biodegradable diluents. Regular composites have been lately recycled to formulate the anionic and cationic fraction of RTIL. Numerous applications of ionic liquids have been explored in segregation discipline. Attributable to the extraordinary polarization as well as exceptional current steadiness, IL-centered immobile segments have been applied to resolution of varied series of critically stimulating complexes frequently extremely polar composites using great boiling points plus physical resemblances comprising elongated sequence fatty acids, essential oils, polycyclic aromatic sulfur heterocycles (PASHs) and PCBs. IL-centered immobile segments facilitated the gas chromatography study for effective as well as precise amount of liquid in the industrialized yields for example pharmaceutical as well as petrochemicals complexes.
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Conference papers on the topic "Cationic-anionic complexes"

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Ge, Xiaojing, Ghith Biheri, Abdulmohsin Imqam, Baojun Bai, and Yuwei Zhang. "Experimental Study: Investigating the Anions and Cations’ Effects on the Elasticity of the Anionic and Cationic High Viscosity Friction Reducers." In SPE Western Regional Meeting. SPE, 2023. http://dx.doi.org/10.2118/213048-ms.

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Abstract High viscosity friction reducers (HVFRs) are widely used as friction-reducing agents and proppant carriers during hydraulic fracturing. The reuse of produced water has gained popularity due to environmental and economic benefits. Currently, the field’s most commonly used friction reducers are anionic and cationic HVFRs. Anionic HVFRs are typically pumped with freshwater, while cationic HVFRs are used with high Total Dissolved Solids (TDS) produced water. Cationic friction reducers are believed to have better TDS tolerance, friction reduction performance, and proppant transport capabilities compared to anionic friction reducers under high TDS conditions due to their superior viscoelastic properties. In addition, the impact of different anions and cations on the viscosity of HVFRs has been thoroughly studied, and viscosity reduction mechanisms include charge shielding, increasing the degree of hydrolysis, and forming coordination complexes. However, anions and cations’ effects on the elasticity of HVFRs still remain to be investigated. Besides, most previous experimental studies either do not specify experimental procedures or control the experimental variables well. Therefore, the ultimate objective of this experimental study is to analyze various cations and anions’ effects on the elasticity of anionic and cationic HVFRs comparably and precisely with experimental variables well controlled. Two hypotheses based on anions and cations’ effects on the viscosity of HVFRs are proposed and will be tested in this study. First, the elasticity reduction of anionic HVFRs is mainly due to cations, whereas the elasticity reduction of cationic HVFRs is mainly due to anions. Second, the salts’ effects on the elasticity reduction of HVFRs should follow the same trend as the salts’ effects on the viscosity reduction of HVFRs. For anionic HVFRs, monovalent Alkali metals should have a similar effect; divalent Alkaline earth metals should have a similar effect; transition metals should have the most severe effect. For cationic HVFRs, SO42- should have more pronounced effects than Cl-. To demonstrate both hypotheses, an anionic and a cationic HVFR at 4 gallons per thousand gallons (GPT) were selected and analyzed. The elasticity measurements of both anionic and cationic HVFRs were conducted with deionized (DI) water and various salts respectively. Fe3+ and H+ (or pH) effects were specifically investigated. The results showed both hypotheses were accepted.
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Puchta, Ralph, and Dušan Ćoćić. "IRM@Be2+ – quantum chemistry between Bavaria and Šumadija." In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.053p.

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Quantum chemical (density functional theory) mechanistic investigations on ligand exchange reactions at a tetrahedrally-coordinated dicationic Beryllium center offer a harmless and alternative way to learn about the traversed reaction pathways compared to experimental studies. Calculations for solvent exchange at [Be(H2O)4]2+, [Be(NH3)]2+, and [Be(HCN)4]2+ showed interchange (I) type mechanisms. To learn about the potential influences of spectator ligands we calculated the water exchange at [Be(L)(H2O)3]n+ (L: neutral ligands, mono-anionic ligands or cationic ligands) and got again consequently I-type paths. The activation energies depend strongly on the starting complexes, e.g., if hydrogen bonds have to be broken. The influence of spectator ligands is limited to the charge of the ligand and therefore the overall charge of the beryllium complex. The small size of the beryllium solvent complexes allows to test tools like AIM to dissect between pure interchange mechanisms, associative mechanisms and dissociative interchange mechanisms based on electron density along the reaction pathway.
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Sun, Hong, Ying-ying Lin, Xi Geng, Lanka Wickramasinghe, Fulya Zalluhoglu, and Qing Wang. "Engineering a Synthetic Friction Reducer to Combat Undesirable Formation of FR-Metal Complex/Precipitation in Slickwater Fracturing." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/217763-ms.

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Abstract During stimulation and production, a highly viscous and rubbery precipitation can form due to incompatibility of friction reducer polymers (cationic, anionic or amphoteric) with ferric ions, particularly in formations with high iron content. This material plugs up proppant packs, even production strings, and is extremely detrimental to well productivity. A straightforward sequestration approach with chelants does not work because of poor outcome and prohibitive economics. Compatible biopolymer FRs, as an alternative approach, have limited applications due to their moderate FR performance compared to synthetic PAM based polymers. This work shows the development of a novel synthetic friction reducer to address this challenge. The polymer was designed by systematically optimizing monomer compositions, molecular weight and surfactant packages. Friction reduction performance of the newly developed FR was evaluated in friction loops under various water conditions. Iron tolerance tests were performed by mixing ferric iron with prehydrated FRs under different pHs, at high concentrations, and salinities. The mixture solutions were then placed in a water bath for heat treatment to simulate downhole conditions and to accelerate the formation of the ferric/FR complexes. Comparative experiments were performed using conventional FRs. In order to probe the interaction between polymers and the iron species, zeta potential analyzer was applied to measure charge changes of the polymer strands. The newly developed FR showed superior FR performance with fast hydration and high overall friction reduction, in both fresh water and synthetic brines. In iron tolerance tests, rubbery precipitations formed in solutions for all three types of conventional FRs, while no such precipitations were observed with the newly developed FR, even in the presence of 500 ppm ferric ion. This test was repeated in a wide range of pH and salinity conditions and no significant viscosity change of the FR polymer solution was observed before and after the test. Zeta potential measurements confirmed the validity of the polymer design to minimize the interaction between the new FR polymer and iron ions. This paper demonstrates that the newly developed friction reducer successfully solves the incompatibility issue of FRs with iron spices, i.e., without flocculation on the surface or formation of gummy precipitations downhole. Its superior friction reduction performance with no concerns of potential damages make it a strong candidate for iron-rich fields. Mechanism of the interaction between iron and synthetic polymers is proposed and confirmed by zeta potential results. The manuscript discusses in depth the strategy of the design of the newly developed copolymer, including selection of monomers, molecular weight control, and inverting surfactants.
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Tymoshenko, Arsenii, Ihor Vorona, Roman Yavetskiy, et al. "Effect Of Mg2++Si4+ Complex Additive On Consolidation Features, Microstructure And Optical Properties Of Yag, Yag:Sm3+ Ceramics." In International Young Scientists Conference on Materials Science and Surface Engineering. Karpenko Physico-Mechanical Institute of the NAS of Ukraine, 2023. http://dx.doi.org/10.15407/msse2023.093.

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The work is devoted to studying of Si4++Mg2+ complex additive for obtaining transparent YAG:Sm3+ ceramics. The processes of densification of the YAG:Si4+,Mg2+ model system, which provides control of solid-state sintering processes due to changes in the concentration of defects in both the anionic and cationic sublattice, were studied. The best result in terms of optical quality (T = 84%) was achieved with YAG:Sm3+ (3 at.%) ceramics doped with 0.071 at% of Si4+ ions and 0.044 at% of Mg2+ ions.
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Mihai, Mihaela. "COMPLEX DERIVED FROM THE MEDIUM ANIONIC POLYELECTROLYTE AND MEDIUM CATIONIC SURFACTANT � NEW COAGULANTS USED IN WASTEWATER TREATMENT." In SGEM2011 11th International Multidisciplinary Scientific GeoConference and EXPO. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2011/s20.111.

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Su, Zhiqing, Yingcheng Li, Jun Jin, Xiujuan He, Hui Xu, and Hui Sun. "Novel Complex Core-Shell Microspheres as Profile Control Agent." In SPE Conference at Oman Petroleum & Energy Show. SPE, 2025. https://doi.org/10.2118/224938-ms.

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Abstract Aiming to achieve depth profile control at fixed points and excellent adaptability in heterogeneous formations, a novel complex polyacrylamide microsphere with a cationic core and anionic shell was synthesized via inverse emulsion polymerization. This microsphere, with its unique structure, demonstrates remarkable adaptability to the complex and varied conditions of heterogeneous formations, providing a reliable profile control agent. The morphology and structure of the core-shell microspheres were characterized using laser scanning confocal microscopy (LSCM), X-ray photoelectron spectroscopy (XPS), and zeta potential measurements. The anionic shell ensures low adsorption on sand in the initial stage, allowing the microspheres to migrate deeply into the reservoir. After the shell degrades, some amide groups in the core hydrolyze to form negatively charged carboxyl groups. The amphoteric microsphere core aggregates through electrostatic attraction, forming larger blocks with high adsorption capacity due to the cationic groups in the core. 3D imaging of the core-shell microspheres, achieved through fluorescent staining of the shell via LSCM, confirmed the core-shell structure. After shell degradation, the core spontaneously aggregates into clusters more than 20 times the initial particle size, significantly enhancing plugging performance and adaptability to heterogeneous formations. The degradation time of the shell can be adjusted by modifying the crosslinking degree. By combining the shell degradation time with the advancement speed of the solution underground, the plugging position of the core-shell microspheres can be precisely controlled. Sand pack plugging experiments evaluated the plugging characteristics of the core-shell microspheres. The results show that these novel flexible core-shell microspheres can diffuse and transport effectively in the initial stage and exhibit superior plugging capability after aging in the reservoir for a specific period. Additionally, the core-shell microspheres can effectively plug cores with a wide range of permeability, facilitating the formation of blocking zones at fixed locations in heterogeneous formations. This novel microsphere represents a breakthrough in profile control technology, offering a new controllable method that is sure to pique the interest of researchers in the field.
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Adila, Ahmed S., Mahmoud Aboushanab, Ahmed Fathy, and Muhammad Arif. "An Experimental Investigation of Surface Chemistry of Rocks in the Presence of Surfactants." In GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219143-ms.

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Abstract Surfactant flooding is a well-known chemical enhanced oil recovery (cEOR) technique. However, surfactant surface chemistry and the associated interactions with rock surfaces are complex and have not been fully investigated. Here, we experimentally investigate the surface chemistry of 15 rock surfaces (10 carbonate and 5 sandstones) upon interaction with different types of surfactants, including cationic, anionic, non-ionic, and zwitterionic surfactants at different concentrations (before, at, and after the critical micelle concentration, CMC). The rock samples were examined using Scanning Electron Microscopy (SEM) to investigate their structure and surface morphology. To understand the interactions at the surfactant-mineral interface and surfactant behavior, the zeta potential measurements of surfactant-brine-rock emulsions were performed, while surface chemical functional groups were identified by Fourier-transform infrared (FTIR) spectroscopy. The zeta potential results show that both anionic (SDS) and cationic (CTAB) surfactants depict better stability, in carbonates and sandstones, compared to the non-ionic (Triton X-100) and zwitterionic (3- (N, N-Dimethylmyristylammonio) surfactants, which is due to the nature of the charge of each surfactant. Also, the FITR results indicate the existence of different chemical bonds and functional groups at different concentrations for each surfactant type, and the magnitude of these bonds differs as a function of rock type and mineralogy. For instance, the rock samples treated with CTAB cationic surfactant reveal the presence of C-O, Mg-C, and Ca-C groups at all concentrations. However, despite being present at all concentrations, these responses show different magnitudes at different surfactant concentrations. The results of this study provide valuable data set to understand the surfactant surface chemistry interactions with different carbonate and sandstone rock surfaces and thus have direct implications for chemical enhanced oil recovery.
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Nag, Okhil Kumar, Han Young Woo, and Wei R. Chen. "Cellular internalization of a membrane binding two-photon probe by a complex of anionic diblock copolymer and cationic surfactant." In SPIE BiOS, edited by Wei R. Chen. SPIE, 2012. http://dx.doi.org/10.1117/12.901836.

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Aften, Carl W., Yaser Asgari, and Sharon Warren. "A Critical Survey of the Rheological Properties Used to Predict Friction Reducer Performance." In SPE Eastern Regional Meeting. SPE, 2022. http://dx.doi.org/10.2118/211874-ms.

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Abstract Increased interest in correlating rheological properties to the prediction of proppant transport and/or friction reduction performance produces sporadic and isolated experimental evidence. Obtaining accurate results specifically for viscosity, proposedly representative of proppant transport and friction reduction, is challenging and therefore, extrapolating polymer melt rheology to dilute polymer solutions is problematic particularly when applying linear viscoelastic theory. This paper presents a simultaneous, multivariable research approach illustrating how viscoelastic results and hypotheses for anionic, cationic, and amphoteric friction reducers in various brines provide insight into the limitations of constricted variable and experimental range methodology. Establishing a relevant application window for viscoelastic friction reducers is complicated. Guar gum linear gels are viscous in nature and more approachable than synthetic friction reducers when manipulated for rheological experimentation and field application extrapolation. However, crosslinking of guar gum linear gels results in a viscoelastic fluid of greater complexity, thus even the simplest of linear gels must be subjected to a variety of unique bench tests differentiated by and specific to individual service companies’ field application requirements. Friction reducers’ crossover of storage and loss moduli are dependent upon how the reducers were dispersed and hydrated with respect to brine characters, times, and mixing energies. Furthermore, correlating rheological measurements developed for the melt state may not appropriately adapt to the friction reducer application's dilute polymer state. Response surfaces were generated for various anionic, cationic, and amphoteric friction reducers with testing variables including brine type, loading, mixing rpm, mixing duration, shear rate, linear shear strain, responses of viscosity, and moduli with corresponding cross over results. Excellent regression was obtained from these complex, interactive response surfaces, revealing the breadth of variability obtained from complex experimentation and validating that studies using simplistic procedures provide limited and potentially biased performance conclusions. When relating rheology to friction reduction and proppant transport, whether in the lab or the field, and understanding the complexities of polymer absolute dispersion, dissolution, and kinetics indicate that, with respect to performance prediction, limited knowledge is gained from simple polymer make down regimens. This work offers a guideline for assimilating comprehensive studies of complex versus oversimplified, limited scope rheological measurement research and analyses.
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Kakadjian, Sarkis, Jarrett Kitchen, and Amanuel Gebrekirstos. "Avoiding Fatal Attractions: How to Prevent Production-Killing Interactions between Wet Sand and Stimulation Fluids." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2025. https://doi.org/10.2118/223549-ms.

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Abstract Improving output from unconventional oil and gas reserves requires the appropriate proppant and chemicals not only to facilitate fracture creation but also to reduce damage to both the proppant pack and the reservoir itself. The interactions between polyacrylamides (PAMs) used as friction reducers (FRs), additives, and p roppants are complex. Variations in water quality such as changes in pH levels and electrolyte concentrations can alter the relative charges of these components. These charge shifts can lead to phenomena like repulsion, absorption, or flocculation among the various components. This study aimed to develop strategies, either chemically or mechanically, to mitigate damage caused by clay, quartz, and feldspar suspensions resulting from interactions between wet sand sources and the fluid system. To achieve this goal, the research team first monitored the turbidity of supernatant samples as well as the conductivity of proppants from different sand mines. Fine adhesion to proppant surfaces was assessed and Zeta Potential measurements were conducted of fines suspended within the fluid system to evaluate flocculation potential. The effects of three PAM-based FRs were compared: a traditional anionic copolymer made from sodium acrylate and acrylamide; a cationic polyacrylamide based on acryloyloxy-ethyl-trimethyl-ammonium chloride (AETAC); and a terpolymer partially substituted with 2-acrylamido tert-butylsulfonic acid (ATBS). Also, the technical group teamed with a sand mine company in South Texas introducing changes on sequency of the sand cyclones during sand processing and following the outcome by turbidity measurements and analyzing the Quartz and Clay type per X-Ray Diffraction. Testing was carried out across various water qualities. Findings indicated that particle bridging of fines by cationic polyme rs within the proppant pack is significantly more influenced by salinity than by anionic polymers. Furthermore, the strength of electrostatic charges on proppant/fines surfaces fluctuates with pH variations. The team evaluated the effect of additives such as surfactants, clay control agents, and biocides in the fracturing fluid on flocculation. Results showed that anionic PAMs performed better in lower-salinity brines containing total dissolved solids (TDS) below 15,000 parts per million (ppm). In contrast, at TDS levels exceeding 30,000 ppm, there were noticeable signs of increased flocculation among suspended particles in the supernatant. On the mechanical approach, processing all sand through twice number of Cyclones increased the levels of Quartz in the sand and decreased actual levels of Migrating Clays from approximately 3.5% to 1.3% also reflected in drop on the Turbidity levels by 90%. These results, combined with the actual conductivity data, is used to further enhance production, and expand the accessibility of local/lower-cost sand mines to reduce supply chain constraints by leveraging wet sand in hydraulic fracturing operation.
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Reports on the topic "Cationic-anionic complexes"

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Wicker, Louise, Ilan Shomer, and Uzi Merin. Membrane Processing of Citrus Extracts: Effects on Pectinesterase Activity and Cloud Stability. United States Department of Agriculture, 1993. http://dx.doi.org/10.32747/1993.7568754.bard.

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The U.S. team studied the role of cations and pH on thermolabile (TL-PE) and thermostable (TS-PE), permeation in ultrafiltration (UF) membranes, affinity to ion exchange membranes, mechanism of cation and pH activation, and effect on PE stability. An optimum pH and cation concentration exists for activity and UF permeation, which is specific for each cation type. Incomplete release of PE from a pectin complex resulted in low PE binding to cationic and anionic membranes. Incubation of PE at low pH increases the surface hydrophobicity, especially TL-PE, but the secondary structure of TL-PE is not greatly affected. The Israeli team showed that stable cloud colloidal constituents flocculate following the conversion of soluble to insoluble biopolymers. First, formation of pectic acid by pectinesterase activity is followed by the formation of calcium pectate gel. This process initiates a myriad of poorly defined reactions that result in juice clarification. Second, protein coagulation by heat resulted in flocculation of proteinacous bound cloud constituents, particularly after enzymatic pectin degradation. Pectinesterase activity is proposed to be an indirect cause for clarification; whereas binding of cloud constituents is the primary event in clarification by pectate gel and coagulated proteins. Understanding the mechanism of interaction of protein and pectic polymers is key to understanding cloud instability. Based on the above, it was hypothesized that the structure of pectin-protein coagulates plays a key role in cloud instability.
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