4-Hydroxystyrene-styrene copolymers

Comparison between the enthalpic parameters log(t) and AHoo %) for PVME or PMMA blends with PHS or styrene-hydroxystyrene (SHS) copolymers makes it possible to discuss the effect of hydrogen bond strength on aging. For example, FTIR measurements on a SHS copolymer with 71 mol.% hydroxystyrene (SHS71) indicated that the strength of the interaction increased in the order SHS71/PMMA... 

Invention relates to a cinnamatic photo-polymerization type homopolymeric or copolymeric alignment material, in which polymaleimide is singly used as the main chain, or is combined with styrene, hydroxystyrene or axryloni-trile to form a copolymer so as to be used as the main chain, or polyimide is used as the main chain. 

Some of block copolymers with styrene derivatives are also amphiphilic, such as methyl vinyl ether-p-alkoxystyrene [88] and alkyl vinyl ether-p-hydroxystyrene (from p-r-butoxystyrene) [89] (Fig. 6). 

Fig. 6 TEM image of a 50 50 diblock copolymer blend of poly(isoprene-l)/ocfc-2-vinylpyridine) (IP) and poly(styrene-6ZocA -4-hydroxystyrene) (SH). Reprinted with permission from [44], 2005 American Chemical Society...

Fig. 46. Effective interaction parameters Xrcp-PS (—) and Xrcp pvp( ) as functions of monomer ratio in the copolymer/for a poly(styrene-d8-co-4-hydroxystyrene) where/is the molar fraction of 4-hydroxystyrene. The dotted line ( = 0.015) is the maximum value for which a strong rcp/homopolymer interface is formed...

Fig. 47. Fracture toughness gc (A) at high copolymer coverage (saturation values), and fraction of deuterium on the PS side of the interface after fracture ( ) at low copolymer coverage, as a function of copolymer composition/, a Poly(styrene-d8-co-4-hydroxystyrene) b poly(styrene-d8-co-4-vinyl-AT-ethylbenzamide) and c poly(styrene-d8-co-4-vinylbenza-mide). Data from [77]...

O-methylated PHOST [179]. This terpolymer was originally developed as a chemically amplified laser resist for circuit board application [180] and then as a single layer 193 nm positive resist [181], which will be described in more detail later. Another interesting three-component approach is the use of a N-acetal polymer as a dissolution inhibitor of poly(3-methyl-4-hydroxystyrene) [182]. A deep UV resist consisting of poly(3-methyl-4-hydroxystyrene-co-4-hydroxystyrene), poly(N,0-acetal), bis(arylsulfonyl)diazomethane, and a photobase was reported from Hoechst (currently Clariant). The function of the photobase is described later. A copolymer of 4-hydroxystyrene with styrene was also employed as a matrix resin. 

Asami has reported grafting of living polyTHF on polymer with pendant alkali phenolates 157). Poly(p-hydroxystyrene-co-styrene) gave 100% grafting efficiency at 0 °C with Na countercations extraction with isopropanol gave 30 %-78 % copolymer the rest being insoluble gel. 

A very prominent example of this type of resist is a copolymer of 4-hydroxy-styrene with tert-butyl ester-protected 4-hydroxystyrene (TBEST) (XXIX) (see scheme 7.33), developed at IBM and sold under the brand name of APEX-E by the Shipley Company. The synthetic route to copolymer (XXIX) can be through direct copolymerization of 4-hydroxystyrene with TBEST or via polymerization of TBEST, followed by partial deprotection to afford a copolymer with repeating units having about 20-30% protecting groups. Partial protection of copolymer... 

A rather unexpected water- and alcohol-insensitive activator, namely boron trifluoride etherate, was developed by Sawamoto for the living polymerization of p-hydroxystyrene in combination with the water adduct of p-methoxystyrene as initiator [78], The polymerizations proceeded even in large excess of water, which is in large contrast with the absolutely dry conditions that are normally required for carbocationic polymerizations. It is proposed that acetonitrile, which is used as polymerization solvent, stabilizes the short-lived carbocationic propagating species. The same polymerization methodology could be applied for the preparation of statistical and block copolymers consisting ofp-hydroxystyrene and b-methoxystyrene [79], as well as for the homopolymerizations of styrene, p-chlorostyrene and p-methylstyrene in the presence of a proton trap [80]. 

Demeftahi. M.V. Frechet, J.M.J. Study of the compatibility of blends of polymers and copolymers containing styrene, 4-hydroxystyrene and 4-vinylpyridine. Polymer 1988. 29. All. 

Iij lijima, T., Suzuki, N., Fukuda, W., Tomoi, M. Toughening of aromatic diamine-cured epoxy resins by modification with hybrid modifiers composed of N-phenylmaleimide-styrene copolymers and N-phenylmaleimide-styrene-p-hydroxystyrene terpolymers. Polym. Intern. 38 (1995) 343-352. 

Copolymerization is the most important synthetic strategy available to tailor the physical, solution and mechanical properties of macromolecules. In this paper the synthesis of well defined random and block copolymers containing monomer units of very different polarity are described. Novel macromolecular architectures incorporating 4-hydroxystyrene, t-butylacrylate and styrene have been prepared to investigate the combined effects of macromolecular architecture and hydrophobicity on thin film aqueous base dissolution. 

A similar synthetic procedure was used to prepare the various random copolymers of (a) 4-acetoxystyrene and styrene or (b) styrene and t-butyl acrylate. Deacetylation of Poly(4-acetoxystyrene-co-styrene) (5). To a slurry of poly(4-acetoxystyrene-co-styrene) (70 30) (2) (10.0 g, 0.069 mol) in methanol at reflux (50 mL), under N2, ammonium hydroxide (5.33 g, 0.152 mol) dissolved in water (10 mL) was added dropwise over 15 minutes. After addition, the reaction mixture was heated at reflux for 18 hours, during which time the polymer went into solution. The reaction is then cooled to room temperature, and the polymer isolated by precipitation into water (500 mL), filtered, washed well with water, and dried in a vacuiun oven overnight at 50°C. Isolated yield of poly(4-hydroxystyrene-co-styrene) (6) 85% of theory. M = 7278, = 8297, PD = 1.14. 

Block Copolymers. Well defined block copolymers of 4-hydroxystyrene and styrene were prepared by firstly, the synthesis of low molecular weight blocks of styrene capped with TEMPO. The molecular weights of these styrene blocks were controlled by the ratio of unimolecular initiator (4) relative to styrene monomer (2). For example, 1-phenyl-l-(2, 2, 6, 6 -tetramethyl-r-piperidinyloxy)ethane (4) (1.67g, 0.0064 mol) was added to styrene (2) (20.0g, 0.192 mol) and heated to 125-130°C, under N2, for 48 hours. The reaction was then cooled to room temperature and the polymer dissolved in tetrahydrofuran (100 mL), and isolated by precipitation into methanol (1000 mL). The TEMPO terminated polystyrene (7) was then filtered, washed with methanol and dried in a vacuum oven overnight at 50°C. Isolated yield 90% of theory. M = 2764, M = 3062, PD = 1.10 (Theoretical A.M.U = 3120). 

These short TEMPO capped styrene blocks (7) were then used as "macroinitiators for the further polymerization of 4-acetoxystrene (1) using the same procedure as described above. The length of the acetoxystyrene block is controlled by the ratio of the "macroinitiator (7) to acetoxystyrene monomer. The acetoxystyrene block was then converted to 4-hydroxystyrene by quantitative base hydrolysis of the acetoxy groups as previously described. Table 1. A similar synthetic strategy was used for the preparation of poly(styrene- co-t-butyl acrylate) block copolymers. 

Well-defined block copolymers of 4-hydroxystyrene and styrene (9) were prepared by the synthesis of low molecular weight blocks of styrene capped with TEMPO (7) (Scheme 2). The molecular weights of these styrene blocks were... 

The acetoxy block was then deactylated by quantitative base hydrolysis of the acetoxy groups to form a block copolymer of poly(4-hydroxystyrene-co-styrene) (9). In all cases, both random and block, the monomer feed ratio was in agreement with the... 

The copolymer architecture of poly(4-hydroxystyrene-co-styrene) was found to have insignificant effect on its dissolution rate (Fig. 57.5 Table 57.12) [36]. On the other hand, incorporation of inert styrene unit into poly(4-hydroxystyrene) drastically reduces dissolution rate. This method of incorporating inert unit has been employed to optimize the dissolution of base polymers for advanced DUV photoresists. 

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