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Radiation‐induced reactions of ring‐substituted polystyrenes analyzed by radiolysis of low molecular‐weight model compounds
Author(s) -
Tanigaki Katsumi,
Tateishi Kazuo,
Ohnishi Yoshitake
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760261608
Subject(s) - radiolysis , polystyrene , chlorine , radical , hydrogen atom abstraction , ring (chemistry) , polymer chemistry , photochemistry , chemistry , resist , hydrogen , derivative (finance) , materials science , organic chemistry , polymer , layer (electronics) , financial economics , economics
Radiation‐induced reactions of polystyrene derivatives have been studied by the radiolysis of ring‐substituted isopropylbenzene derivatives, i. e., 4‐amino. 4‐hydroxy, 4‐methoxy, 4‐methyl, 4‐chloromethyl, 4‐chloro, and 4‐acetyl derivatives. Low‐temperature ESR analyses measured at 77 K indicate that. In general, the a‐position is the most sensitive site to radiation and that thus a‐radicals are produced through a‐hydrogen removal. However, among these derivatives, the amino, acetyl, chloromethyl, and. chloro derivatives undergo different reactions from the other derivatives. A phCOCH 3 cleavage from the‐ acetyl derivative and NH cleavage from the amino derivative occur, and chlorine removal takes place from the chloro‐methyl and chloro derivatives. Final products detected by gas chromatography‐mass spectrometry indicate not only that radiation‐induced free radical recombination occurs. but also that if chlorine is produced by radiation, hydrogen abstraction by radiation‐induced chlorine takes place prior to the free radical recombination. The susceptibility of each derivative to hydrogen abstraction by radiation‐induced active chlorine increases, as the electron‐donation of ring‐substituents is increased. Based on the clarified reaction mechanism, the design of polystyrene derivatives as resist materials is discussed and two new types of resist systems are described. One is a new chloromethylstyrene based blend resist, which is formulated from poly(4‐meth‐oxystyrene) and poly(4‐chloromethylstyrene). The other is a new non‐swelling alkaline developable negative resist, which is formulated from poly(4‐hydroxystyrene) and a chlorine‐releasing compound.