Journal articles: 'Self-assembled monolayer (SAM)'

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Takeuchi, Kai, Junsha Wang, Beomjoon Kim, Tadatomo Suga, and Eiji Higurashi. "Room temperature bonding of Au assisted by self-assembled monolayer." Applied Physics Letters 122, no. 5 (January 30, 2023): 051603. http://dx.doi.org/10.1063/5.0128187.

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The surface activated bonding (SAB) technique enables room temperature bonding of metals, such as Au, by forming metal bonds between clean and reactive surfaces. However, the re-adsorption on the activated surface deteriorates the bonding quality, which limits the applicability of SAB for actual packaging processes of electronics. In this study, we propose and demonstrate the prolongation of the surface activation effect for room temperature bonding of Au by utilizing a self-assembled monolayer (SAM) protection. While the bonding without SAM fails after exposure of the activated Au surface to ambient air, the room temperature bonding is achieved using SAM protection even after 100 h exposure. The surface analysis reveals that the clean and activated Au surface is protected from re-adsorption by SAM. This technique will provide an approach of time-independent bonding of Au at room temperature.

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Jennane, Jamila, Tanya Boutros, and Richard Giasson. "Photolithography of self-assembled monolayers: optimization of protecting groups by an electroanalytical method." Canadian Journal of Chemistry 74, no. 12 (December 1, 1996): 2509–17. http://dx.doi.org/10.1139/v96-281.

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Patterned surfaces presenting a high density of chemically reactive functional groups can be prepared through photolithography of self-assembled monolayers (SAM). In this paper, we report the synthesis and the evaluation of three reagents that can be used in SAM-photolithographic applications. These reagents are made up of a triethoxysilylpropylamine moiety in which the amine is temporarily blocked by photolabile protecting groups: NVOC (o-nitroveratryloxycarbonyl), ONB (o-nitrobenzyl), or DDZ (α,α-dimethyl-3,5-dimethoxybenzyloxycarbonyl). The presence of the triethoxysilyl group allows self-assembled monolayer formation. Release of chemically reactive amino groups is achieved by irradiation of the surface. An electroanalytical method was developed and used to monitor and optimize the three steps of the methodology occurring on surfaces: monolayer formation, photodeprotection, and subsequent functionalization of the released amino groups. Quantitative information on the efficiency of the photodeprotection step was obtained by this method. It was found that the DDZ group is superior to the ONB and NVOC photolabile protecting groups for SAM-photolithographic applications. Percentages of liberated amino groups are generally above 50% with the DDZ group, while they are generally inferior to 25% and 2% for NVOC and ONB, respectively. These differences are attributed to the destruction of some of the released amino groups through a subsequent reaction with the photoproduct, o-nitrosobenzaldehyde for ONB and 3,4-dimethoxy-6-nitrosobenzaldehyde for NVOC, and to partial loss or destruction of the monolayer during prolonged irradiations. Key words: self-assembled monolayers, surface modification, photolithography, photolabile protecting groups, cyclic voltammetry.

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Lykova, Maria, Iuliana Panchenko, Ulrich Künzelmann, Johanna Reif, Marion Geidel, M. Jürgen Wolf, and Klaus-Dieter Lang. "Characterisation of Cu/Cu bonding using self-assembled monolayer." Soldering & Surface Mount Technology 30, no. 2 (April 3, 2018): 106–11. http://dx.doi.org/10.1108/ssmt-10-2017-0033.

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Purpose Cu/Cu diffusion bonding is characterised by high electrical and thermal conductivity, as well as the mechanical strength of the interconnects. But despite a number of advantages, Cu oxidises readily upon exposure to air. To break through the adsorbed oxide-layer high temperature and pressure, long bonding time and inert gas atmosphere are required during the bonding process. This paper aims to present the implementation of an organic self-assembled monolayer (SAM) as a temporary protective coating that inhibits Cu oxidation. Design/methodology/approach Information concerning elemental composition of the Cu surface has been yielded by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy. Two types of substrates (electroplated and sputtered Cu) are prepared for thermocompression bonding in two different ways. In the first case, Cu is cleaned with dilute sulphuric acid to remove native copper oxide. In the second case, passivation with SAM followed the cleaning step with dilute sulphuric acid. Shear strength, fracture surface, microstructure of the received Cu/Cu interconnects are investigated after the bonding procedure. Findings The XPS method revealed that SAM can retard Cu from oxidation on air for at least 12 h. SAM passivation on the substrates with sputtered Cu appears to have better quality than on the electroplated ones. This derives from the results of the shear strength tests and scanning electron microscopy (SEM) imaging of Cu/Cu interconnects cross sections. SAM passivation improved the bonding quality of the interconnects with sputtered Cu in comparison to the cleaned samples without passivation. Originality/value The Cu/Cu bonding procedure was optimised by a novel preparation method using SAMs which enables storage and bonding of Si-dies with Cu microbumps at air conditions while remaining a good-quality interconnect. The passivation revealed to be advantageous for the smooth surfaces. SEM and shear strength tests showed improved bonding quality for the passivated bottom dies with sputtered Cu in comparison to the samples without SAM.

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Araki, Yuki, Taito Sekine, Ryongsok Chang, Tomohiro Hayashi, and Hiroshi Onishi. "Molecular-scale structures of the surface and hydration shell of bioinert mixed-charged self-assembled monolayers investigated by frequency modulation atomic force microscopy." RSC Advances 8, no. 43 (2018): 24660–64. http://dx.doi.org/10.1039/c8ra03569e.

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Petrovic, Marian, Ivan Talian, Lenka Skantarova, Andrej Orinak, and Dusan Velic. "TOF-SIMS surface analysis of L-Tryptophan self assembled monolayer." Open Chemistry 12, no. 5 (May 1, 2014): 568–76. http://dx.doi.org/10.2478/s11532-014-0515-5.

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AbstractThis paper dealt with the preparation and characterization of self — assembled monolayersSAM-s of 1-hexadecanethiole and mercapto acetic acid on the silver nanostructure and subsequently the immobilization with amino acid L-Tryptophane. In order to achieve it, we used the electrodeposition of silver onto nanostructured surface of paraffin impregnated graphite electrode (PIGE). Subsequently, we assembled SAM by choosing the 1-hexadecanethiole and mercaptoacetic acid. These two kinds of SAM underwent the functionalization by L-Tryptophan. The observations of silver on PIGE surfaces were performed by scanning electron microscope (SEM). For surface analysis of the SAM functionalized by L-tryphophan, the TOF-SIMS technique was chosen. Finally, the fragmented ions of the immobilized-L-Tryptophan SAM were determined on the basis of suggested residues and three-dimensional structure. The residues show that the ability of L-Tryptophan to build homogeneous structure is better by mercaptoacetic acid SAM structure than by 1-hexadecanethiol. It was observed that L-Tryptophan built compact surface, which, due its chemical properties, can represent very interesting side regarding biocompatibility, homochirality and robustness in the area of life science.

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Neves, Bernardo R. A., Michael E. Salmon, Phillip E. Russell, and E. Barry Troughton. "Comparative Study of Field Emission-Scanning Electron Microscopy and Atomic Force Microscopy to Assess Self-assembled Monolayer Coverage on Any Type of Substrate." Microscopy and Microanalysis 5, no. 6 (November 1999): 413–19. http://dx.doi.org/10.1017/s1431927699990475.

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Abstract: In this work, we show how field emission–scanning electron microscopy (FE-SEM) can be a useful tool for the study of self-assembled monolayer systems. We have carried out a comparative study using FE-SEM and atomic force microscopy (AFM) to assess the morphology and coverage of self-assembled monolayers (SAM) on different substrates. The results show that FE-SEM images present the same qualitative information obtained by AFM images when the SAM is deposited on a smooth substrate (e.g., mica). Further experiments with rough substrates (e.g., Al grains on glass) show that FE-SEM is capable of unambiguously identifying SAMs on any type of substrate, whereas AFM has significant difficulties in identifying SAMs on rough surfaces.

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Singh, Mandeep, Navpreet Kaur, and Elisabetta Comini. "The role of self-assembled monolayers in electronic devices." Journal of Materials Chemistry C 8, no. 12 (2020): 3938–55. http://dx.doi.org/10.1039/d0tc00388c.

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Today, the self-assembled monolayer (SAM) approach for surface functionalization is regarded as highly versatile and compelling, especially in the immobilization of biomolecules and fabrication of novel supramolecular architectures.

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HABIB, HUMA, M. YASAR, S. MEHMOOD, SAIMA RAFIQUE, A. S. BHATTI, and AISHA NAEEM. "THE KINETICS OF THE AS GROWN AND ANNEALED SELF-ASSEMBLED MONOLAYER STUDIED BY FORCE SPECTROSCOPY." Surface Review and Letters 25, no. 02 (February 2018): 1850054. http://dx.doi.org/10.1142/s0218625x18500543.

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The growth of biological systems like DNA, peptides and proteins are accredited to the self-assembly processes from the molecular level to the nanoscale. The flawless immobilization of DNA on any surface is quite an important step to the development of DNA-based biosensors. The present paper reports the use of atomic force microscopy to determine the mechanical properties of the as grown and annealed self-assembled monolayer (SAM) as well as the mutated DNA immobilized on the SAM. The SAM of alkane thiol (16-mercapto-1-hexadecanol) was developed on Au surface, which was then annealed and analyzed for its structural and mechanical properties. The surface coverage, height and monolayer’s order was studied as a function of incubation time and annealing time. Excessive annealing led to the defragmentation and desorption of SAM structures due to breaking of hydrocarbon bonds. AFM was employed to determine the detach separation, pull-off and work of adhesion of the as grown and annealed SAM.

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Yang, Ki Yeon, Jong Woo Kim, Sung Hoon Hong, and Heon Lee. "Patterning of the Self-Assembled Monolayer Using the Zero Residual Nano-Imprint Lithography." Solid State Phenomena 124-126 (June 2007): 523–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.523.

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Self-Assembled Monolayer (SAM) is a single layer of ordered molecules absorbed on a surface by chemical bonding between the molecular head group and the surface. The surface properties can be controlled by the terminal functional group of the SAM layer. In order to utilize SAM layers for device applications, SAM layer needs to be patterned as a sub-micron size. Patterning of SAM layer in sub-micron size has been done by various techniques including direct-writing by dip-pen nano lithography, selective etching with UV photons, and selective deposition of SAM layer by &-contact printing. In this study, silane based SAM layer was patterned to the sub-micron size using zero residual Nano imprint Lithography, which is regarded as next generation lithography technique due to its simplicity, high throughput and high resolution pattern transferring capability. Using zero-residual layer imprinting, 300nm~2um sized SAM patterns can successfully fabricated. In order to check the surface property of patterned SAM layer, a solution containing nano Ag particles was spin-coated on the SAM patterned substrate and nano Ag particles were selectively deposited on the substrate.

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Escalera-López, D., E. Gómez, and E. Vallés. "Electrochemical growth of CoNi and Pt–CoNi soft magnetic composites on an alkanethiol monolayer-modified ITO substrate." Physical Chemistry Chemical Physics 17, no. 25 (2015): 16575–86. http://dx.doi.org/10.1039/c5cp02291f.

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CoNi and Pt–CoNi magnetic layers on indium-tin oxide (ITO) substrates modified by an alkanethiol self-assembled monolayer (SAM) have been electrochemically obtained as an initial stage to prepare semiconducting layer-SAM-magnetic layer hybrid structures.

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Pratihar, Subha, Swapnil C. Kohale, Dhruv G. Bhakta, Julia Laskin, and William L. Hase. "Dynamics of energy transfer and soft-landing in collisions of protonated dialanine with perfluorinated self-assembled monolayer surfaces." Phys. Chem. Chem. Phys. 16, no. 43 (2014): 23769–78. http://dx.doi.org/10.1039/c4cp03535f.

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Laroussi, Arwa, Małgorzata Kot, Jan Ingo Flege, Noureddine Raouafi, and Vladimir Mirsky. "Self-Assembled Monolayers from Symmetrical Di-Thiols: Preparation, Characterization and Application for the Assembly of Electrochemically Active Films." Engineering Proceedings 6, no. 1 (May 17, 2021): 17. http://dx.doi.org/10.3390/i3s2021dresden-10112.

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1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on a gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact angle measurements. The SAM structure depends on the adsorption conditions. A short incubation time of the electrode at high concentration of this di-thiol leads to the predominating binding through one thiol group of the adsorbate to the gold surface, while a long incubation at low concentration leads to the predominating binding by both thiol groups. A comparative study of the desorption and replacement of SAMs indicates a strong stability increase when the SAM molecules bond gold surfaces by two bonds mainly. This monolayer was used to immobilize electrochemically active p-benzoquinone moiety. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10−10 mol cm−2, which corresponds to the functionalization of 65 ± 5% of SAM molecules. The obtained highly stable SAM with redox-active terminal group can be applied for different tasks of chemical sensing and biosensing. As an example, an application of this system for electrocatalytical oxidation of dihydronicotinamide adenosine dinucleotide (NADH) was tested.

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Bai, Tao, and Xian Hua Cheng. "The Effects of the Self-Assembly Time on the Preparation of Lanthanum-Based Thin Films on Sulfonated 3-Mercaptopropyl Trimethoxysilane." Applied Mechanics and Materials 164 (April 2012): 284–88. http://dx.doi.org/10.4028/www.scientific.net/amm.164.284.

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Lanthanum-based thin films are deposited on the oxidized 3-mercaptopropyl trimethoxysilane self-assembled monolayer (MPTS-SAM) based on the chemisorption of the sulfonic group. The surface energy, chemical composition, phase transformation and surface morphology of the films are analyzed by using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The experimental results indicate that the lanthanum-based thin films are absorbed on oxidized MPTS-SAM and lanthanum element with different oxidation states exists in the thin films deposited on the surface of self-assembly monolayers. The content of lanthanum on the oxidized MPTS-SAM increases with the extension of the assembly time and the rare earth reached saturation when the time was 6h.

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Salman, S. A., N. Akira, Kensuke Kuroda, and Masazumi Okido. "Deposition of Self-Assembled Monolayer on Vanadate Conversion Coated AZ31 Mg Alloy." Materials Science Forum 783-786 (May 2014): 1482–87. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1482.

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Self-assembled monolayer (SAM) was adsorbed on the surface of vanadate conversion coated AZ31 magnesium alloy. The SAM thin film was deposited using (Tridecafluoro-1, 1, 2, 2-tetrahydrooctyl) trimethoxysilane (FAS13) and Tetrakis (trimethylsiloxy) titanium as a catalyst. Contact angles measurement, SEM, XRD, EDS and XPS were employed to analyze the surface morphologies, molecular composition, phase structure and wettability of the coatings formed on Mg alloy substrate. Corrosion resistance property of the coatings was also examined using the anodic polarization method and salt spray test. The anticorrosion property was improved with SAM post treatment. Furthermore, the contact angle increases from 12 deg. to 165 deg. indicating to production of super hydrophobic surface with SAM post treatment.

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Park, Jun Hyung, Buyng Su Park, Gu Huh, Seung Hyun Lee, Hyun Sook Lee, Il Hoon Cho, Se Hwan Paek, and Hai Won Lee. "Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio." Solid State Phenomena 121-123 (March 2007): 495–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.495.

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We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.

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Choi, Bongseok, Masanobu Iwanaga, Hideki T. Miyazaki, Yoshimasa Sugimoto, Akihiro Ohtake, and Kazuaki Sakoda. "Overcoming metal-induced fluorescence quenching on plasmo-photonic metasurfaces coated by a self-assembled monolayer." Chemical Communications 51, no. 57 (2015): 11470–73. http://dx.doi.org/10.1039/c5cc04426j.

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Richards, John F., E. Barry Troughton, Richard A. Dennis, and Phillip E. Russell. "Atomic Force Microscopy Studies of Aluminum Corrosion Inhibition by Adsorbed Self Assembled Monolayers." Microscopy and Microanalysis 3, S2 (August 1997): 1263–64. http://dx.doi.org/10.1017/s1431927600013209.

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Atomic force microscopy (AFM) studies on the microstructure of the phosphonic acid (PA) / Al (with native oxide) self assembled monolayer (SAM) system (a possible corrosion resistant coating interface monolayer) has been evaluated as a function of molecular chain length and processing conditions (i.e. adsorption time) in previous works. It was apparent from the AFM topography and phase images of the monolayer microstructure that the octadecylphosphonic acid (OPA) monolyer was the most conformal and showed little dependence on adsorption time (for times ≤ 24 hours). It was therefore chosen as the most promising monolayer compound of the PA/A1 system with which to study corrosion inhibiting properties.In this present work, AFM is used to study the corrosion inhibiting ability of OPA SAMs on aluminum, and also to investigate the “nucleation” and progression of Al corrosion and oxide formation in water at the nanometer level; with and without SAM passivation.

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Taglietti, Angelo, Giacomo Dacarro, Daniele Barbieri, Lucia Cucca, Pietro Grisoli, Maddalena Patrini, Carla Renata Arciola, and Piersandro Pallavicini. "High Bactericidal Self-Assembled Nano-Monolayer of Silver Sulfadiazine on Hydroxylated Material Surfaces." Materials 12, no. 17 (August 28, 2019): 2761. http://dx.doi.org/10.3390/ma12172761.

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Anti-infective surfaces are a modern strategy to address the issue of infection related to the clinical use of materials for implants and medical devices. Nanocoatings, with their high surface/mass ratio, lend themselves to being mono-layered on the material surfaces to release antibacterial molecules and prevent bacterial adhesion. Here, a “layer-by-layer” (LbL) approach to achieve a self-assembled monolayer (SAM) with high microbicidal effect on hydroxylated surfaces is presented, exploiting the reaction between a monolayer of thiolic functions on glass/quartz surfaces and a newly synthesized derivative of the well-known antibacterial compound silver sulfadiazine. Using several different techniques, it is demonstrated that a nano-monolayer of silver sulfadiazine is formed on the surfaces. The surface-functionalized materials showed efficient bactericidal effect against both Gram-positive and Gram-negative bacteria. Interestingly, bactericidal self-assembled nano-monolayers of silver sulfadiazine could be achieved on a large variety of materials by simply pre-depositing glass-like SiO2 films on their surfaces.

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Xia, Ao, Guo Qiang Tan, Hong Yan Miao, Ya Yu Song, and Hai Yang Bo. "ZrO₂ Thin Films Prepared by Self-Assembled Method." Advanced Materials Research 105-106 (April 2010): 485–87. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.485.

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Octadecyltrichlorosilane (OTS) was prepared on glass substrate to form self-assembled monolayer (OTS-SAM). The OTS-SAM was then UV-irradiated to endow the film with good chemisorption ability. Zirconia films were formed on silanol SAM by the LPD method. The phase structure and surface configuration of the zirconia films were studied by XRD and SEM respectively. The XRD results indicate that the as-deposited ZrO2 thin films are pure tetragonal phase after being annealed at 500°C for 1 h. SEM images show the zirconia film is uniform, but not very compacted.

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Chambrier, Isabelle, David A. Russell, Derek E. Brundish, William G. Love, Giulio Jori, M. Magaraggia, and Michael J. Cook. "Porphyrin self-assembled monolayers and photodynamic oxidation of tryptophan." Journal of Porphyrins and Phthalocyanines 14, no. 01 (January 2010): 81–88. http://dx.doi.org/10.1142/s1088424610001696.

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The zinc and magnesium metalated derivatives of 5,5′-[12,12′-di(thiododecyloxy)-4,4′-phenyl)]-10,10′,15,15′,20,20′-hexakis(3,3′,4,4′,5,5′-hexakisdecyloxyphenyl)diporphyrin, 1b and 1c, have been synthesised and deposited to form self-assembled monolayer (SAM) films on the surface of gold-coated glass substrates. The SAM films have been characterized by RAIR spectroscopy and fluorescence spectroscopy. The potential for the porphyrin films to catalyze the oxidation of tryptophan within human serum albumin upon irradiation with white light has been demonstrated and attributed to the porphyrins acting as photosensitizers of oxygen to form oxidizing species.

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Fan, Zhitao, Chao Zhi, Lei Wu, Pei Zhang, Chengqiang Feng, Liang Deng, Bingjun Yu, and Linmao Qian. "UV/Ozone-Assisted Rapid Formation of High-Quality Tribological Self-Assembled Monolayer." Coatings 9, no. 11 (November 18, 2019): 762. http://dx.doi.org/10.3390/coatings9110762.

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UV/ozone (UVO)-assisted formation of self-assembled monolayer (SAM) of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDS) was prepared on a glass surface. The effect of UVO exposure time on surface roughness and hydrophilicity was investigated through goniometer and atomic force microscope (AFM), and deposition time-dependent SAM quality was detected by AFM and X-ray photoelectron spectroscopy (XPS). The glass surface became smooth with UVO radiation after 10 min, and the hydrophilicity was also improved after the treatment. Confirmed by surface topography detection and chemical composition analysis, a high-quality SAM can be formed rapidly on glass with 10 min UVO treatment followed by 2 h deposition in PFDS solution. Excellent tribological performances of SAM coated with UVO treatment glass were demonstrated by friction and wear tests on AFM compared to film-deposited glass without UVO treatment and original glass. The study sheds a light on preparing high-quality lubrication and antiwear self-assembled films on the surface of engineering materials.

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YAO, FENGFENG, YANBO PEI, and XIUDONG SUN. "CURRENT RECTIFICATION IN NEMATIC LIQUID CRYSTAL CELL WITH ALKANETHIOL SELF-ASSEMBLED MONOLAYER." Journal of Nonlinear Optical Physics & Materials 17, no. 04 (December 2008): 495–501. http://dx.doi.org/10.1142/s0218863508004408.

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Asymmetric current–voltage (I/V) behaviors with respect to the polarity of the voltage bias were observed in the nematic liquid crystal (NLC) cells constructed with the gold film on the silicon wafer as one substrate and an indium-tin-oxide (ITO)-coated glass slide as the other substrate. A little smaller current resulted at the positive bias corresponding to the positive voltage bias being applied to the gold film relative to the ITO-coated glass slide. When the alkanethiol self-assembled monolayer (SAM) was introduced into the above NLC cell as the aligning layer, it was able to enhance the forward current significantly, but suppress the reverse current. A current rectification ratio of ~20 was obtained at 1.5 V in the NLC cell with SAM as the aligning layer. Besides, we also characterized the effect of the optical power of 632.8 nm on the asymmetric I/V behaviors in the NLC cells without SAM and with SAM as the aligning layer.

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Minamiki, Tsukuru, and Ryoji Kurita. "Potentiometric detection of biogenic amines utilizing affinity on a 4-mercaptobenzoic acid monolayer." Analytical Methods 11, no. 9 (2019): 1155–58. http://dx.doi.org/10.1039/c8ay02616e.

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Tsai, Meng-Yen, and Jui-Che Lin. "Preconditioning Gold Substrates Influences Organothiol Self-assembled Monolayer (SAM) Formation." Journal of Colloid and Interface Science 238, no. 2 (June 2001): 259–66. http://dx.doi.org/10.1006/jcis.2001.7522.

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Isozaki, Katsuhiro, Tomoya Taguchi, Kosuke Ishibashi, Takafumi Shimoaka, Wataru Kurashige, Yuichi Negishi, Takeshi Hasegawa, Masaharu Nakamura, and Kazushi Miki. "Mechanistic Study of Silane Alcoholysis Reactions with Self-Assembled Monolayer-Functionalized Gold Nanoparticle Catalysts." Catalysts 10, no. 8 (August 9, 2020): 908. http://dx.doi.org/10.3390/catal10080908.

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The self-assembled monolayer (SAM)-modified metallic nanoparticles (MNPs) often exhibit improved chemoselectivity in various catalytic reactions by controlling the reactants’ orientations adsorbed in the SAM; however, there have been a few examples showing that the reaction rate, i.e., catalytic activity, is enhanced by the SAM-modification of MNP catalysts. The critical parameters that affect the catalytic activity, such as the supports, nanoparticle size, and molecular structures of the SAM components, remain uninvestigated in these sporadic literature precedents. Here, we report the mechanistic investigation on the effects of those parameters on the catalytic activity of alkanethiolate SAM-functionalized gold nanoparticles (AuNPs) toward silane alcoholysis reactions. The evaluation of the catalytic reaction over two-dimensionally arrayed dodecanethiolate SAM-functionalized AuNPs with different supports revealed the electronic interactions between AuNPs and the supports contributing to the rate enhancement. Additionally, an unprecedented size effect appeared—the AuNP with a 20 nm radius showed higher catalytic activity than those at 10 and 40 nm. Infrared reflection–absorption spectroscopy revealed that the conformational change of alkyl chains of the SAM affects the entrapment of reactants and products inside the SAM, and therefore brings about the acceleration effect. These findings provide a guideline for further applying the SAM-functionalization technique to stereoselective organic transformations with designer MNP catalysts.

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Song, Lijian, Youchen Zhang, Weimin Yang, Jing Tan, and Lisheng Cheng. "Molecular Structure Effect of a Self-Assembled Monolayer on Thermal Resistance across an Interface." Polymers 13, no. 21 (October 28, 2021): 3732. http://dx.doi.org/10.3390/polym13213732.

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Understanding heat transfer across an interface is essential to a variety of applications, including thermal energy storage systems. Recent studies have shown that introducing a self-assembled monolayer (SAM) can decrease thermal resistance between solid and fluid. However, the effects of the molecular structure of SAM on interfacial thermal resistance (ITR) are still unclear. Using the gold–SAM/PEG system as a model, we performed nonequilibrium molecular dynamics simulations to calculate the ITR between the PEG and gold. We found that increasing the SAM angle value from 100° to 150° could decrease ITR from 140.85 × 10−9 to 113.79 × 10−9 m2 K/W owing to penetration of PEG into SAM chains, which promoted thermal transport across the interface. Moreover, a strong dependence of ITR on bond strength was also observed. When the SAM bond strength increased from 2 to 640 kcal⋅mol−1Å−2, ITR first decreased from 106.88 × 10−9 to 102.69 × 10−9 m2 K/W and then increased to 123.02 × 10−9 m2 K/W until reaching a steady state. The minimum ITR was obtained when the bond strength of SAM was close to that of PEG melt. The matching vibrational spectra facilitated the thermal transport between SAM chains and PEG. This work provides helpful information regarding the optimized design of SAM to enhance interfacial thermal transport.

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Vakamulla Raghu, Swathi Naidu, and Manuela Sonja Killian. "Wetting behavior of zirconia nanotubes." RSC Advances 11, no. 47 (2021): 29585–89. http://dx.doi.org/10.1039/d1ra04751e.

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In this work, we investigate the wettability of octadecylphosphonic acid (OPA) self-assembled monolayer (SAM) modified ZrO2 nanotubes (ZrNT) of varied morphologies synthesized via electrochemical anodization of zirconium.

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Kang, Boseok, Wi Hyoung Lee, Hyun Ho Choi, Yeong Don Park, and Kilwon Cho. "Built-in water resistance in organic transistors modified with self-assembled monolayers." RSC Adv. 4, no. 85 (2014): 45082–87. http://dx.doi.org/10.1039/c4ra07227h.

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We systematically investigated the effects of a self-assembled monolayer (SAM), prepared on the gate dielectric, on the performances of bottom-gate organic field-effect transistor (OFET) devices under various humid environments.

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Cui, Bao Feng, Jian Min Chen, Jun Yan Zhang, and Hui Di Zhou. "Preparation and Characterization of Poly Amide Amine (Generation 4.0) Self-Assembled Monolayer on Si (100)." Key Engineering Materials 373-374 (March 2008): 645–48. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.645.

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The fourth generation of poly amide amine molecular self-assembled monolayer (PAMAM (G4.0)-SAM) was prepared on hydroxylated Si (111) substrate by a self-assembled technique from specially formulated solution. The PAMAM (G4.0)-SAM were characterized by means of contact angle measurement, ellipsometry, X-ray photoelectron spectroscope (XPS), and atomic force microscopy (AFM). The tribological properties of the as-prepared thin films sliding against a steel ball were evaluated on a friction and wear tester. The tribological results show that the friction coefficient of monocrystal line silicon substrate reduces from 0.6 to 0.18 due to the formation of PAMAM-SAMs on its surface. And the PAMAM (G4.0) -SAM has longer wear life (18000 sliding pass). It is demonstrated that PAMAM (G4.0) -SAM exhibited good wear resistant property. In conclusion, the PAMAM (G4.0)-SAM which possesses good wear resistant property was successfully prepared and the film.

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Puchnin, Kirill, Vitaliy Grudtsov, Maria Andrianova, Stanislav Bezzubov, and Alexander Kuznetsov. "A Surface Modifier for the Production of Selectively Activated Amino Surface Groups." Coatings 9, no. 11 (November 2, 2019): 726. http://dx.doi.org/10.3390/coatings9110726.

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The formation of self-assembled monolayers with the possibility of selective activation is an important goal of surface chemistry. In this work, a new surface modifier which creates amino surfaces based on aminopropylsilatrane (APS) with a protected amino group was obtained. The utilization of protected APS allows producing a self-assembled monolayer (SAM) and obtaining reactive surface amino groups at distinct times. Furthermore, a precise selective deprotection with a further modification of the activated amino groups could be performed without affecting the protected groups. To demonstrate the practical applicability of this modifier, a trinitrotoluene-sensitive sensor based on an ion-sensitive field-effect transistor (ISFET) was obtained.

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Omori, Yuya, Hiroyuki Sakaue, Takayuki Takahagi, and Hitoshi Suzuki. "Self-Spreading of Lipid Bilayer on a Hydrophobic Surface Made by Self-Assembled Monolayer with Short Alkyl Chain." Journal of Nanoscience and Nanotechnology 16, no. 4 (April 1, 2016): 3426–30. http://dx.doi.org/10.1166/jnn.2016.12307.

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Behaviors of self-spreading of lipid bilayer membrane on a glass surface modified with selfassembled monolayer (SAM) with short alkyl chain were observed with fluorescence microscopy. Hydrophobic surface made by SAM was found to hamper the self-spreading phenomenon but the lipid bilayer spread on a hydrophilic one where SAM was decomposed by oxidation. On a binary surface having a hydrophobic region and a hydrophilic one, the lipid bilayer spread on the hydrophilic region but it stopped at the boundary of the hydrophobic region.

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Feng, Bo, A. Liu, N. Wu, Jie Weng, Shu Xin Qu, Jian Xin Wang, and Xiong Lu. "Nano-HA Coating on Titanium Surface Fabricated by Modulation of Self-Assembled Monolayer and Bovine Serum Albumin." Materials Science Forum 561-565 (October 2007): 1529–32. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1529.

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Bone-like hydroxyapatite (HA) coatings were fabricated on titanium implants by a self-assembled technique and biomimetic method. After titanium plates were oxidized in a mixture of H2SO4/H2O2, a hexadecanoic acid self-assembled onto titanium surfaces. Contact angles of water and tricresyl phosphate on the surfaces were measured to characterize the self-assembled monolayer (SAM) and confirm the presence of the functional group. The titanium plates with SAM were used to fabricate HA coatings. In the simulate body fluid (SBF) with and without bovine serum albumin (BSA), Ca2+ and PO4 3- ions could spontaneously deposit onto the titanium surfaces and form bone-like HA coatings. The morphology, component and structure of samples were examined by scanning electronic microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and attenuated total reflection Fourier transform infrared spectroscopy. The results suggested that the SAM can induce the formation of the nano-HA coating with a network and microporous structure. For the biomimetical HA coating induced by HDA-SAM, BSA could modulate the growth of HA crystal and decreased the grain size.

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Honarmand, Ebrahim, and Mohammad Hassan Motaghedifard. "Immobilization of a novel synthesized Schiff base on the surface of a gold electrode for the electrochemical study of adrenaline." Analytical Methods 7, no. 12 (2015): 4995–5005. http://dx.doi.org/10.1039/c5ay00695c.

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A self-assembled monolayer of 2-[({2-[(2-{[(Z)-1-(2-hydroxy phenyl) methylidene] amino} phenyl) disulfanyl] phenyl} imino) methyl] phenol was fabricated on a bare gold electrode (SITP-Au SAM electrode).

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Liu, Chang Song, Dong Mei Zheng, Ji Gen Zhou, Yong Wan, and Zhi Wen Li. "Fabrication of Surface Energy Gradients Using Self-Assembled Monolayer Surfaces Prepared by Photodegradation." Materials Science Forum 688 (June 2011): 102–6. http://dx.doi.org/10.4028/www.scientific.net/msf.688.102.

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A new technique, direct photodegradation of self-assembled monolayers (SAM), to obtain surface energy gradients on Si substrates was demonstrated. The gradient surface, with hydrophobic to hydrophilic gradients, was prepared by two steps: Firstly, a homogeneous fluoroalkylsilane SAM film was deposited by a chemical vapor deposition on a Si substrate. Secondly, a controlled photodegradation technique was directly applied to the homogeneous FAS-SAM surface. The surface energy gradient was then obtained due to the different intensity of photoirradiation in the different positions along the photodegraded path on the SAM surfaces. The resulting surface displayed a gradient of wettability (with the contact angle of water changing from 55° to 18°) over a distance of 4.2 mm. The water droplet was driven by surface energy gradient and spontaneously moved from the hydrophobic to hydrophilic surface. During the moving process, the water droplet accelerated firstly and then decelerated. The peak velocity was about 23.3 mm/s. The velocity is dependent on the gradient of the surface energy.

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Ghosh, Tamal, K. Krushnamurthy, Asisa Kumar Panigrahi, Asudeb Dutta, Ch Subrahmanyam, Siva Rama Krishna Vanjari, and Shiv Govind Singh. "Facile non thermal plasma based desorption of self assembled monolayers for achieving low temperature and low pressure Cu–Cu thermo-compression bonding." RSC Advances 5, no. 125 (2015): 103643–48. http://dx.doi.org/10.1039/c5ra17735a.

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This paper reports Self Assembled Monolayer (SAM) of propanethiol desorption assisted low temperature, low pressure Cu–Cu thermo-compression bonding, a technique which could be applied to developing next generation heterogeneous smart devices.

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Han, Won-Kyu, Jin-Ki Cho, Jae-Woong Choi, Jeong-Tae Kim, Seung-Jin Yeom, Noh-Jung Kwak, Jin-Woong Kim, and Sung-Goon Kang. "Pd Seed Layer for Electroless Cu Deposition on TaN Diffusion Barrier by Self-Assembled-Monolayer Method(SAM)." Korean Journal of Materials Research 17, no. 9 (September 27, 2007): 469–74. http://dx.doi.org/10.3740/mrsk.2007.17.9.469.

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37

Škugor Rončević, Ivana, Nives Vladislavić, Marijo Buzuk, and Maša Buljac. "Electrodeposition of hydroxyapatite coating on Mg alloy modified with organic acid self-assembled monolayers." Journal of Chemical Research 44, no. 3-4 (December 31, 2019): 212–20. http://dx.doi.org/10.1177/1747519819895980.

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Calcium phosphate coatings are used in orthopedics due to their excellent bioactivity, which improves the bonding between the metal implant and the bone. The use of self-assembling monolayers of long-chain organic acids can induce calcium phosphate growth. In this article, the self-assembling monolayers of stearic acid and octadecylphosphonic acid formed on the Mg alloy surface were additionally modified with electrodeposited hydroxyapatite coating to increase the bioactivity and biocompatibility of the Mg alloy in a physiological solution. Hydroxyapatite coating was prepared by a two-step reaction: hydrogen phosphate formed by electrodeposition at constant potential was converted into hydroxyapatite coating through an acid–base reaction. The results obtained by voltammetry and electrochemical impedance spectroscopy have shown a beneficial effect of organic acid self-assembling monolayer and especially of organic acid self-assembling monolayer modification by hydroxyapatite electrodeposition on the corrosion properties of Mg alloy in physiological solution. Fourier transform infrared spectroscopy and scanning electron microscopy were used to verify the existence of the organic acid SAM|HAp film on the Mg alloy surface and their morphology.

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Ichiyanagi, Kouhei, Hiroshi Sekiguchi, Tokushi Sato, Shunsuke Nozawa, Ayana Tomita, Manabu Hoshino, Shin-ichi Adachi, and Yuji C. Sasaki. "Cooling dynamics of self-assembled monolayer coating for integrated gold nanocrystals on a glass substrate." Journal of Synchrotron Radiation 22, no. 1 (January 1, 2015): 29–33. http://dx.doi.org/10.1107/s1600577514019730.

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Picosecond time-resolved X-ray diffraction has been used to study the nanoscale thermal transportation dynamics of bare gold nanocrystals and thiol-based self-assembled monolayer (SAM)-coated integrated gold nanocrystals on a SiO2glass substrate. A temporal lattice expansion of 0.30–0.33% was observed in the bare and SAM-coated nanocrystals on the glass substrate; the thermal energy inside the gold nanocrystals was transported to the contacted substrate through the gold–SiO2interface. The interfacial thermal conductivity between the single-layered gold nanocrystal film and the SiO2substrate is estimated to be 45 MW m−2 K−1from the decay of the Au 111 peak shift, which was linearly dependent on the transient temperature. For the SAM-coated gold nanocrystals, the thermal dissipation was faster than that of the bare gold nanocrystal film. The thermal flow from the nanocrystals to the SAM-coated molecules promotes heat dissipation from the laser-heated SAM-coated gold nanocrystals. The thermal transportation of the laser-heated SAM-coated gold nanocrystal film was analyzed using the bidirectional thermal dissipation model.

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Dai, Zhenghong, Srinivas K. Yadavalli, Min Chen, Ali Abbaspourtamijani, Yue Qi, and Nitin P. Padture. "Interfacial toughening with self-assembled monolayers enhances perovskite solar cell reliability." Science 372, no. 6542 (May 6, 2021): 618–22. http://dx.doi.org/10.1126/science.abf5602.

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Iodine-terminated self-assembled monolayer (I-SAM) was used in perovskite solar cells (PSCs) to achieve a 50% increase of adhesion toughness at the interface between the electron transport layer (ETL) and the halide perovskite thin film to enhance mechanical reliability. Treatment with I-SAM also increased the power conversion efficiency from 20.2% to 21.4%, reduced hysteresis, and improved operational stability with a projected T80 (time to 80% initial efficiency retained) increasing from ~700 hours to 4000 hours under 1-sun illumination and with continuous maximum power point tracking. Operational stability–tested PSC without SAMs revealed extensive irreversible morphological degradation at the ETL/perovskite interface, including voids formation and delamination, whereas PSCs with I-SAM exhibited minimal damage accumulation. This difference was attributed to a combination of a decrease in hydroxyl groups at the interface and the higher interfacial toughness.

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40

Klutse, Charles K., Adam Mayer, Julia Wittkamper, and Brian M. Cullum. "Applications of Self-Assembled Monolayers in Surface-Enhanced Raman Scattering." Journal of Nanotechnology 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/319038.

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The increasing applications of surface-enhanced Raman scattering (SERS) has led to the development of various SERS-active platforms (SERS substrates) for SERS measurement. This work reviews the current optimization techniques available for improving the performance of some of these SERS substrates. The work particularly identifies self-assembled-monolayer- (SAM-) based substrate modification for optimum SERS activity and wider applications. An overview of SERS, SAM, and studies involving SAM-modified substrates is highlighted. The focus of the paper then shifts to the use of SAMs to improve analytical applications of SERS substrates by addressing issues including long-term stability, selectivity, reproducibility, and functionalization, and so forth. The paper elaborates on the use of SAMs to achieve optimum SERS enhancement. Specific examples are based on novel multilayered SERS substrates developed in the author’s laboratory where SAMs have been demonstrated as excellent dielectric spacers for improving SERS enhancement more than 20-fold relative to conventional single layer SERS substrates. Such substrate optimization can significantly improve the sensitivity of the SERS method for analyte detection.

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41

Shrotriya, P., K. K. S. Karuppiah, R. Zhang, A. Chandra, and S. Sundararajan. "Surface stress generation during formation of alkanethiol self-assembled monolayer (SAM)." Mechanics Research Communications 35, no. 1-2 (January 2008): 43–49. http://dx.doi.org/10.1016/j.mechrescom.2007.09.007.

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42

Tian, Ranran, Mengbo Luo, and Jingyuan Li. "Spontaneous protein desorption from self-assembled monolayer (SAM)-coated gold nanoparticles." Physical Chemistry Chemical Physics 20, no. 1 (2018): 68–74. http://dx.doi.org/10.1039/c7cp05515c.

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43

Yasutake, Yuhsuke, Zujin Shi, Toshiya Okazaki, Hisanori Shinohara, and Yutaka Majima. "Interaction Control Between Endohedral Metallofullerene and Metal Substrate by Introducing Alkanethiol Self-Assembled Monolayer." Journal of Nanoscience and Nanotechnology 6, no. 11 (November 1, 2006): 3460–63. http://dx.doi.org/10.1166/jnn.2006.034.

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The interaction control between endohedral metallofullerenes and a metal substrate has been demonstrated by introducing hexanethiol, octanethiol, and decanethiol self-assembled monolayers (SAMs) as the interlayer. We observe the electric properties of terbium endohedral metallofullerenes (Tb@C82) on alkanethiol SAMs with different chain lengths by scanning tunneling microscopy (STM) and spectroscopy (STS). Based on the comparison of the high-resolution STM images of a Tb@C82 molecule on hexanethiol and octanethiol SAMs, the interaction between Tb@C82 and a hexanethiol SAM is found to be larger than that between Tb@C82 and an octanethiol SAM; this is because at 68 K, the rotational states of Tb@C82 terminate only on the hexanethiol SAM. Furthermore, we find that the tunneling current-voltage characteristics of Tb@C82 on the hexanethiol SAM show the rectifying effects that are also caused by the molecular energy level shifts of Tb@C82 molecules due to the large interaction.

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44

Lan, Wen-Chien, Ta-Sen Huang, Yung-Chieh Cho, Yueh-Tzu Huang, Christopher J. Walinski, Pao-Chang Chiang, Muhammad Rusilin, Fang-Tzu Pai, Chien-Chia Huang, and Mao-Suan Huang. "The Potential of a Nanostructured Titanium Oxide Layer with Self-Assembled Monolayers for Biomedical Applications: Surface Properties and Biomechanical Behaviors." Applied Sciences 10, no. 2 (January 14, 2020): 590. http://dx.doi.org/10.3390/app10020590.

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This study investigated the surface properties and biomechanical behaviors of a nanostructured titanium oxide (TiO) layer with different self-assembled monolayers (SAMs) of phosphonate on the surface of microscope slides. The surface properties of SAMs were analyzed using scanning electron microscopy, X-ray photoemission spectroscopy, and contact angle goniometry. Biomechanical behaviors were evaluated using nanoindentation with a diamond Berkovich indenter. Analytical results indicated that the homogenous nanostructured TiO surface was formed on the substrate surface after the plasma oxidation treatment. As the TiO surface was immersed with 11-phosphonoundecanoic acid solution (PUA-SAM/TiO), the formation of a uniform SAM can be observed on the sample surface. Moreover, the binding energy of O 1s demonstrated the presence of the bisphosphonate monolayer on the SAMs-coated samples. It was also found that the PUA-SAM/TiO sample not only possessed a higher wettability performance, but also exhibited low surface contact stiffness. A SAM surface with a high wettability and low contact stiffness could potentially promote biocompatibility and prevent the formation of a stress shielding effect. Therefore, the self-assembled technology is a promising approach that can be applied to the surface modification of biomedical implants for facilitating bone healing and osseointegration.

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45

Kajisa, Taira, and Toshiya Sakata. "Bioanalytical Method Based on Extended-Gate Field-Effect Transistor Modified by Self-Assembled Monolayer." International Journal of Automation Technology 12, no. 1 (January 5, 2018): 52–63. http://dx.doi.org/10.20965/ijat.2018.p0052.

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In this paper, we introduce semiconductor biosensors for detecting or monitoring various biological substances and for surface chemical technologies tailored to target molecules. To fabricate the semiconductor biosensor best suited to the target biomolecules, the gate electrodes for extended-gate type field-effect transistors (EGFETs), which are separated from semiconductor part, must be constructed by interfacial chemical modification. First, ion-sensitive EGFET was developed by self-assembled monolayer (SAM) modification on gold gate electrode. Polar functional-group-terminated alkanethiol SAM-coated-gate FET showed pH dependency. In particular, carboxy-terminated alkanethiol SAM-coated gate FET showed higher sensitivities from 42 to 56 mV/pH, which was close to the Nernstian response, in a wide range of biological environments. By using the ion-sensitive EGFET, the hydroxyapatite biomineralization process was successfully monitored by increasing the gate surface potential. Furthermore, saccharides were quantified using EGFET by changing the functional group of SAM, with phenylboronic acid as a functional molecule. In conclusion, target-specific surface modification on gate electrodes makes it possible for semiconductor devices to be applied as biosensors.

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46

Balakrishnan, Divya, Wouter Olthuis, and César Pascual García. "Redox Active Self-Assembled Monolayer Functioning as a pH Actuator." Proceedings 2, no. 13 (November 21, 2018): 1073. http://dx.doi.org/10.3390/proceedings2131073.

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Using electrochemical control to change the chemical environment in liquids is quite challenging because the small surface to volume ratio offered by traditional cells limits the release or modification of chemicals from the electrodes. Here we present the control of proton concentration (acidity) using a combination of a redox active SAM, which allows ease of fabrication, control of the chemical reactions and repeatability, with a microfluidic design that provides large range and stability over time of the set acidity point, quasi-reversibility during several cycles, and capacity of miniaturization and scalability for multiplexing.

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47

Ono, Sotaro, Satoshi Usui, Seong-Ho Kim, Kuniaki Tanaka, Rigoberto C. Advincula, and Hiroaki Usui. "Effect of Reactive Self-Assembled Monolayer at the Anode Interface of Organic Light-Emitting Diode." Journal of Nanoscience and Nanotechnology 16, no. 4 (April 1, 2016): 3407–13. http://dx.doi.org/10.1166/jnn.2016.12314.

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Organic light-emitting diodes (OLEDs) were prepared on indium-tin oxide (ITO) substrates that were modified with various self-assembled monolayers (SAMs) including those which have reactive terminal units. The OLED performance was analyzed in terms of molecular length, dipole moment and HOMO level of SAM molecules estimated by the density functional theory calculation. It was suggested that the current efficiency of OLED is partly improved by controlling the carrier balance, interfacial dipole moment, and electron energy level by SAM modification. More importantly, remarkable improvement in OLED efficiency was achieved by chemically tethering the inorganic/organic interface via benzophenone-terminated SAM. The reactive SAM having benzophenone terminal group can be a promising tool to control the inorganic/organic interface for organic devices.

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Malytskyi, Volodymyr, Jean-Jacques Simon, Lionel Patrone, and Jean-Manuel Raimundo. "Synthesis, self-assembly and characterization of a novel push–pull thiophene-based chromophore on a gold surface." RSC Advances 5, no. 33 (2015): 26308–15. http://dx.doi.org/10.1039/c5ra02200b.

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A self-assembled dense monolayer based on a non-charged push–pull chromophore is clearly evidenced by electrochemical, XPS and STM analysis. Associated with good film properties a conducting behavior consistent with the structure of the SAM-organized push–pull is also shown.

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Shen, Cai, and Manfred Buck. "Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond." Beilstein Journal of Nanotechnology 5 (March 10, 2014): 258–67. http://dx.doi.org/10.3762/bjnano.5.28.

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The intercalation of Cu at the interface of a self-assembled monolayer (SAM) and a Au(111)/mica substrate by underpotential deposition (UPD) is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM–substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S–Au and S–Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH) this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different.

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Fischer, Ulrich Christian, Carsten Hentschel, Florian Fontein, Linda Stegemann, Christiane Hoeppener, Harald Fuchs, and Stefanie Hoeppener. "Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer." Beilstein Journal of Nanotechnology 5 (September 3, 2014): 1441–49. http://dx.doi.org/10.3762/bjnano.5.156.

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A general concept for parallel near-field photochemical and radiation-induced chemical processes for the fabrication of nanopatterns of a self-assembled monolayer (SAM) of (3-aminopropyl)triethoxysilane (APTES) is explored with three different processes: 1) a near-field photochemical process by photochemical bleaching of a monomolecular layer of dye molecules chemically bound to an APTES SAM, 2) a chemical process induced by oxygen plasma etching as well as 3) a combined near-field UV-photochemical and ozone-induced chemical process, which is applied directly to an APTES SAM. All approaches employ a sandwich configuration of the surface-supported SAM, and a lithographic mask in form of gold nanostructures fabricated through colloidal sphere lithography (CL), which is either exposed to visible light, oxygen plasma or an UV–ozone atmosphere. The gold mask has the function to inhibit the photochemical reactions by highly localized near-field interactions between metal mask and SAM and to inhibit the radiation-induced chemical reactions by casting a highly localized shadow. The removal of the gold mask reveals the SAM nanopattern.

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Journal articles on the topic 'Self-assembled monolayer (SAM)'

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