The Experts below are selected from a list of 3291 Experts worldwide ranked by ideXlab platform
Raghavachari Dhamodharan - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and characterization of statistical copolymers of styrene and 4-(1-hydroxyalkyl)styrene
Journal of Applied Polymer Science, 2004Co-Authors: Mohammed J. Nasrullah, Raghavachari DhamodharanAbstract:A family of new polymers based on poly(4-(1-hydroxyalkyl)styrene), and its copolymers with styrene were synthesized and thoroughly characterized by 1H-NMR, 13C-NMR, FTIR, and UV spectroscopies. The chemical modification reactions of polystyrene (PS) was used as a novel method of performing the synthesis of poly(4-(1-hydroxyethyl-co-styrene)), poly(4-(1-hydroxypropyl-co-styrene)), poly(4-(1-hydroxybutyl-co-styrene)), and poly(4-(1-hydroxyphenylmethyl-co-styrene)). The novelty of this method lies in the incorporation of the desired mol % of the functional groups in polystyrene chain, to obtain random copolymers of desired composition. In preliminary testing/evaluation studies the utility and versatility of the new copolymers, which have the potential to be negative-tone Photoresist Materials, were studied. Thus a few Photoresist formulations based on poly(styrene-co-4-(1-hydroxyalkylstyrene)) were developed with 5 wt % of a photoacid generator. These studies suggested that the new copolymers synthesized by a simple and alternate method could have the same potential as a Photoresist Material when compared with the polymers synthesized by the polymerization of the corresponding functional monomer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1902–1914, 2004
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A practical route for the preparation of poly(4‐hydroxystyrene), a useful Photoresist Material
Journal of Polymer Science Part A: Polymer Chemistry, 2000Co-Authors: Mohammed J. Nasrullah, S. Raja, K. Vijayakumaran, Raghavachari DhamodharanAbstract:The synthesis and characterization of poly(4-hydroxystyrene) (PHS) and poly(4-vinylphenol) (PVPh) by the polymer modification route are reported. Polystyrene prepared by free-radical and anionic polymerization was acetylated quantitatively to poly(4-acetylstyrene) (ACPS) with acetyl chloride and anhydrous aluminum trichloride in carbon disulfide. The acetylation worked equally well in a mixture of 1,2-dichloroethane (DCE) and nitrobenzene containing largely DCE. The extent of the acetylation was estimated by 1 H NMR. The oxidation of ACPS was carried out with various oxidizing agents and reaction conditions. The peracetic acid oxidation in chloroform resulted in quantitative oxidation to poly(4-acetoxystyrene) (APS) as estimated by 1 H NMR spectroscopy. The treatment of APS with hydrazine hydrate in dioxane resulted in the formation of PVPh. Deacetylation occurred with equal versatility in a mixture of aqueous sodium hydroxide and tetrahydrofuran. All the polymers were characterized via gel permeation chromatography, IR, UV, 1 H NMR, and 13 C NMR spectroscopic techniques. This is the first report on the synthesis of ACPS, APS, and PHS of reasonably narrow molecular weight distributions or otherwise by the polymer modification route.
Sang Yup Lee - One of the best experts on this subject based on the ideXlab platform.
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Simple Patterning of Cells on a Biocompatible Nonchemically Amplified Resist
Macromolecular Rapid Communications, 2006Co-Authors: Jin-baek Kim, Ramakrishnan Ganesan, So Young Yoo, Jae-hak Choi, Sang Yup LeeAbstract:A simple lithographic process in conjunction with a novel biocompatible nonchemically amplified Photoresist Material was successfully used for cell patterning. UV light irradiation on selected regions of the nonchemically amplified resist film renders the exposed regions hydrophilic by the formation of carboxylic groups. Mouse fibroblast cells were found to be preferentially aligned and proliferated on the UV light exposed regions of the nonchemically amplified resist film where carboxylic groups were present.
Mohammed J. Nasrullah - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and characterization of statistical copolymers of styrene and 4-(1-hydroxyalkyl)styrene
Journal of Applied Polymer Science, 2004Co-Authors: Mohammed J. Nasrullah, Raghavachari DhamodharanAbstract:A family of new polymers based on poly(4-(1-hydroxyalkyl)styrene), and its copolymers with styrene were synthesized and thoroughly characterized by 1H-NMR, 13C-NMR, FTIR, and UV spectroscopies. The chemical modification reactions of polystyrene (PS) was used as a novel method of performing the synthesis of poly(4-(1-hydroxyethyl-co-styrene)), poly(4-(1-hydroxypropyl-co-styrene)), poly(4-(1-hydroxybutyl-co-styrene)), and poly(4-(1-hydroxyphenylmethyl-co-styrene)). The novelty of this method lies in the incorporation of the desired mol % of the functional groups in polystyrene chain, to obtain random copolymers of desired composition. In preliminary testing/evaluation studies the utility and versatility of the new copolymers, which have the potential to be negative-tone Photoresist Materials, were studied. Thus a few Photoresist formulations based on poly(styrene-co-4-(1-hydroxyalkylstyrene)) were developed with 5 wt % of a photoacid generator. These studies suggested that the new copolymers synthesized by a simple and alternate method could have the same potential as a Photoresist Material when compared with the polymers synthesized by the polymerization of the corresponding functional monomer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1902–1914, 2004
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A practical route for the preparation of poly(4‐hydroxystyrene), a useful Photoresist Material
Journal of Polymer Science Part A: Polymer Chemistry, 2000Co-Authors: Mohammed J. Nasrullah, S. Raja, K. Vijayakumaran, Raghavachari DhamodharanAbstract:The synthesis and characterization of poly(4-hydroxystyrene) (PHS) and poly(4-vinylphenol) (PVPh) by the polymer modification route are reported. Polystyrene prepared by free-radical and anionic polymerization was acetylated quantitatively to poly(4-acetylstyrene) (ACPS) with acetyl chloride and anhydrous aluminum trichloride in carbon disulfide. The acetylation worked equally well in a mixture of 1,2-dichloroethane (DCE) and nitrobenzene containing largely DCE. The extent of the acetylation was estimated by 1 H NMR. The oxidation of ACPS was carried out with various oxidizing agents and reaction conditions. The peracetic acid oxidation in chloroform resulted in quantitative oxidation to poly(4-acetoxystyrene) (APS) as estimated by 1 H NMR spectroscopy. The treatment of APS with hydrazine hydrate in dioxane resulted in the formation of PVPh. Deacetylation occurred with equal versatility in a mixture of aqueous sodium hydroxide and tetrahydrofuran. All the polymers were characterized via gel permeation chromatography, IR, UV, 1 H NMR, and 13 C NMR spectroscopic techniques. This is the first report on the synthesis of ACPS, APS, and PHS of reasonably narrow molecular weight distributions or otherwise by the polymer modification route.
Virgil Percec - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of well‐defined Photoresist Materials by SET‐LRP
Journal of Polymer Science Part A: Polymer Chemistry, 2010Co-Authors: Sven Fleischmann, Virgil PercecAbstract:Single electron transfer-living radical polymerization (SET-LRP) provides an excellent tool for the straightforward synthesis of well-defined macromolecules. Heterogeneous Cu(0)-catalysis is employed to synthesize a novel Photoresist Material with high control over the molecular architecture. Poly(γ-butyrolactone methacrylate)-co-(methyladamantly methacrylate) was synthesized. Kinetic experiments were conducted demonstrating that both monomers, γ-butyrolactone methacrylate (GBLMA) and methyl adamantly methacrylate (MAMA), are successfully homopolymerized. In both cases polymerization kinetic is of first order and the molecular weights increase linearly with conversion. The choice of a proper solvent was decisive for the SET-LRP process and organic solvent mixtures were found to be most suitable. Also, the kinetic of the copolymerization of GBLMA and MAMA was investigated. Following first order kinetics in overall monomer consumption and exhibiting a linear relationship between molecular weights and conversion a "living" process was established. This allowed for the straightforward synthesis of well-defined Photoresist polymers.
Carlton G Willson - One of the best experts on this subject based on the ideXlab platform.
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Mesoscale Monte Carlo Simulation of Photoresist Processing
Journal of The Electrochemical Society, 2004Co-Authors: Gerard M. Schmid, Michael D. Stewart, Sean D. Burns, Carlton G WillsonAbstract:Progress toward a comprehensive, chemically detailed, mesoscale Photoresist simulation with predictive capability is reported. The semiconductor industry has developed a need for mechanistically detailed simulations capable of studying Photoresist performance at nanometer dimensions. The nanometer-scale dimensional tolerances on Photoresist features are becoming increasingly difficult to meet and expensive to produce in high-volume manufacturing processes. A mesoscale Monte Carlo simulation for processing of positive tone, chemically amplified Photoresists has been developed to enable detailed study of Photoresist performance as a function of formulation and processing variables. In this model, the molecular components of the Photoresist Material are included explicitly within a three-dimensional lattice framework. Molecular level models for each processing step have been derived from experimental studies and are implemented in the simulation modules for the several Photoresist processing steps. Simulation input variables are fundamental and measurable Material properties and processing parameters. Empirical calibrations to expensive lithography experiments are not used. The mesoscale nature of the simulation offers the ability to study the stochastic processes that contribute to resist feature roughness, while the chemical detail included in the models enables investigation of the wide Photoresist formulation variable space. This suite of programs provides a unique tool to guide the rational design of new Photoresist Materials.