ABSTRACT In photoinduced cationic ring‐opening polymerization (ROP) of epoxy monomers, chain‐transfer reactions in the presence of alcohols are well established, and monosulfides are known to inhibit polymerization even at very low loadings (i.e., 0.01 mol%). Herein, it is thoroughly investigated the role of a disulfide‐containing diol in quenching the polymerization of a difunctional epoxy formulation. Differently from the monosulfide, the propagation can start, and only at high sulfur:epoxy ratio the reactions of the disulfides with the oxonium ions effectively compete with the propagation and stops the polymerization. This inhibition mechanism can be exploited as a novel maskless photolithographic approach, enabling the spatially controlled patterning of epoxy coatings through localized deposition of the disulfide diol. As a proof of concept, sharply defined features with sizes down to 200 µm are successfully fabricated. These results introduce disulfide‐mediated polymerization quenching as a versatile and material‐efficient method for epoxy photopatterning.
Spessa et al. (Thu,) studied this question.