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A water-developable negative photoresist based on the photocrosslinking of N-phenylamide groups was prepared by the copolymerization of 4-styrenesulfonic acid sodium salts (SSS) with N-phenylmethacrylamide (copolymer A) or p-hydroxy-N-phenylmethacrylamide (copolymer B), and its properties such as solubility changes, photochemical reaction, and photoresist characteristics were studied. The copolymer containing a relatively higher amount of SSS units was soluble in water. Solubility changes of the copolymers in the various buffer solutions of pH 4 ϳ 11 and in water upon irradiation were observed by the measurement of insoluble fraction. The copolymers were soluble in water before irradiation, whereas they became insoluble upon irradiation with the UV light of 254 nm. The photochemical reaction of the copolymer studied by the UV and IR absorption spectroscopies indicated that a photoFries rearrangement was favored for copolymer A, whereas a photocrosslinking reaction was predominate for copolymer B. Resist properties of the copolymers were studied by measurement of the normalized thickness and by development of the micropattern. Negative tone images with a resolution of 1 m were obtained with these materials that have a sensitivity (D g 0.5 ) of ϳ 1100 mJ/cm 2 with an aqueous developing process.

Copolymers containing oxime‐urethane groups were prepared by the copolymerization of methyl methacrylate and benzophenoneoximinocarbonylaminoethyl methacrylate (BCM), and their photochemical properties were examined from the UV and IR absorption spectral changes. The decomposed fraction of oxime‐urethane groups in the copolymer increased with irradiation time, but it decreased with the content of BCM units in the copolymer. Changes of the surface properties of the copolymer film on irradiation were studied by measurements of the contact angle and dyeing with an acid dye. The surface of the copolymer film changed to become more hydrophilic upon irradiation with 254 nm of UV light. After the irradiated copolymer films were treated with HCl or methanol, changes of the contact angle of water on irradiation were compared. The copolymer film was dyed by acid dyes after treatment of the irradiated film with HCl. The degree of dyeing increased with irradiation time and BCM units in the copolymer, but it was unaffected by the film thickness. Various colors were developed on the irradiated area depending on the acid dye as the developer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1200–1207, 2002

Temperature gradient interaction chromatography (TGIC) analysis of polyisoprene (PI) is reported. PI can be fractionated in terms of molecular weight with high resolution by TGIC using a C18 bonded silica column as the stationary phase and a mixture of CH2Cl2/CH3CN (80/20, v/v) as the mobile phase. The temperature was increased during the elution from 5°C to 34°C to optimize the fractionation of high molecular weight PI. The relatively poor resolution in the low molecular weight range was improved by changing the eluent composition. For example, all the oligomeric species from the unimer to the 29mer of a low molecular weight PI (average mol. wt.: 900) were fully resolved with the mixed eluent of CH2Cl2/CH3CN (50/50, v/v) and a linear temperature program from 5°C to 40°C. In addition, simultaneous size exclusion chromatography and TGIC fractionation of PI/polystyrene, PI/poly(methylmethacrylate) mixtures are also reported.