The synthesis and characterization of diethyl oxomalonate-, glycerol-, and nitroglycerin-functionalized polystyrene (DPS, GPS, and NGPS) from polystyrene (PS) by the chemical-modification route were explored. DPS was synthesized by the Friedel-Crafts acylation of PS with diethyl oxomalonate in the presence of SnCl4 by a batchwise-addition process. Proton NMR studies indicate that the acylation was essentially quantitative. IR spectroscopy was additionally used to confirm the transformation. The reduction of DPS was carried out using various reduction agents and reaction conditions. The sodium hydride reduction in tetrahydrofuran resulted in a quantitative conversion to GPS as estimated by 1H NMR spectroscopy. Treatment of GPS with a nitrating mixture of nitric and sulfuric acids results in the formation of NGPS. All the polymers were characterized using gel permeation chromatography, IR, UV, 1H spectroscopic techniques, pyrolysis-mass spectrometry, and thermogravimetric analysis. This is the first investigation on the syntheses of DPS, GPS, and NGPS. © 2001 John Wiley &amp; Sons, Inc.

R. Dhamodharan

Department Of Chemistry

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Polymer Science, Part A: Polymer Chemistry

Several synthetic approaches are available to make photoresist polymers for deep UV (DUV) lithography. Two approaches were widely used in semiconductor manufacturing: i) direct polymerization of corresponding monomers by (controlled) radical, (living) ionic polymerization ii) thermal or chemical catalyzed deprotection or protection of the macromolecules. The latter approach which is also called polymer modification chemistry (PMC) or polymer analogous chemistry offers several advantageous over the direct polymerization approach. In this presentation, we will provide an overview on the preparation and basic lithographically important characterization of new polymers based on poly(4-(1-hydroxyalkyl)styrene-co-styrene) [Poly(4-HAS-co-S)]. These polymers were synthesized for the first time by PMC and this methodology is an simple alternative for the synthesis of poly(4-HAS-co-S) than conventionally used synthetically challenging free radical or low temperature anionic polymerization of the protected monomer. We have synthesized high and low molecular weight (Mn) polymers with mole fraction of functional group ranging from partial to complete functionalization. Several formulations based on poly(4-HAS-co-S) were developed and tested for negative tone imaging at DUV lithography. Lithographic performance of these polymers at DUV lithography will be compared with their molecular weight and mole fraction of functional groups.

Proceedings of SPIE - The International Society for Optical Engineering

Poly4-(1-hydroxyalkyl)styrene based photoresist materials: Design, synthesis and their lithographic performance

The preparation and properties of barbiturate- and thiobarbiturate- functionalized polystyrenes [(BAPS) & (TBAPS)] synthesized by the chemical modification of polystyrene homopolymer are discussed. The fluorescence emissions of the polymers are found to be dependent on the nature of the substituent, as well as its concentration and this is estimated as well. Fluorescence microscopic studies of BAPS and TBAPS in water indicated the formation of polymeric aggregates in a solution of about 5 μm. Surface tension measurements confirmed the formation of aggregated structures in aqueous solution. The polymers synthesized are observed to chelate a wide variety of metal ions, the % uptake of which is observed to increase with increasing mol% of the pendant functional groups.

Journal of Macromolecular Science - Pure and Applied Chemistry

Synthesis and properties of Polystyrene Carrying Pendant Hydroxybarbiturate Groups

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.

Journal of Applied Polymer Science

Synthesis and characterization of statistical copolymers of styrene and 4-(1-hydroxyalkyl)styrene

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 1H 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 1H 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, 1H NMR, and 13C 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.

Practical route for the preparation of poly(4-hydroxystyrene), a useful photoresist material

Key Engineering Materials

Partial Transient Liquid Phase Metals Layer-Surface Coating for Improved Oxidation Resistance and Low Cycle Fatigue Crack Initiation Life at 1073K in Air of TiAl Alloy

Journal	Journal of Polymer Science, Part A: Polymer Chemistry
ISSN	0887624X
Open Access	No