Synthesis of electrophoretic poly(ester-sulfone) gel via thiol-yne click gelation

Abstract

The thiol-ene 'click' reaction is well known as an efficient method for synthesizing certain functional polymers. In this study, we performed the ternary 'click' copolymerization (gelation) of bis(butynyl) methylsuccinate (BYM), bis(butenyl) methylsuccinate and 3,6-dioxa-1,8-octanedithiol (TEGDT) to synthesize a poly(ester-sulfide) gel. In this process, an alkenyl sulfide was initially formed before undergoing a second thiol addition to afford a poly(ester-sulfide) gel, which finally afforded the poly(ester-sulfone) gel after oxidation using Oxone. The gelation process was characterized via a model reaction using 1-octyne, 1-octene and TEGDT. The results clearly indicate that a thiol first added to the BYM unit during the click gelation and that the addition of the second thiol to the subsequent alkenyl sulfide was faster than the addition to the alkene. The synthesized poly(ester-sulfone) gel was anode-selectively deposited onto a stainless-steel electrode by electrophoretic deposition, although the parent poly(ester-sulfide) gel was not.