Chloromethyl group, sensitization polystyrene

We note from Table VIII a strong interest in halogenated resists, particularly those substituted with chlorine. The addition of chlorine to the aromatic structure of polystyrene has a marked effect on cross-linking efficiency. Monodisperse polystyrene, for example, has a sensitivity on the order of 50 p C/cm2, yet with as little as 20% chloromethyl groups substituted on the ring, the sensitivity is improved to 2 C/cm2 for comparable molecular weight and distribution. 

Sensitization of degradation has been achieved by copolymerizing acenaphthylene, and chloromethyl vinyl ketone. The mode of action of benzo-phenone has been attributed to its ability to sensitive decomposition of hydroperoxide groups. Blends of polystyrene with poly(phenylene oxide) have attracted some attention. " It is worth noting that the last paper reports that singlet oxygen had no effect on pure polystyrene or its blends. ... 

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