One-pot two-step lipase-catalyzed synthesis of ?,?-thiophene-capped poly(?-caprolactone) macromonomers and their use in electropolymerization

Abstract

Macromonomers based on poly(epsilon-caprolactone) (PCL) with alpha,omega-thiophene functional end groups were prepared in bulk by enzymatic polymerization using immobilized Candida Antarctica lipase B (Novozym 435) as the catalyst. In the synthesis strategy, 3-thiophenemethanol was used to initiate the enzyme-assisted ring-opening polymerization of epsilon-caprolactone (epsilon-CL) to yield PCL with alpha-thiophene end group (initiation reaction, ThPCL) and then 3-thiopheneacetic acid was added to prepolymerized epsilon-CL to introduce omega-thiophene functionality in termination step (ThPCLTh). Macromonomers were characterized by H-1 and C-13 NMR, FTIR, and GPC. Moreover, the obtained macromonomers were employed in electropolymerization experiments and copolymers with thiophene or pyrrole were synthesized through their end thiophene groups. These polymers were characterized by cyclic voltammetry (CV), FTIR, and scanning electron microscopy (SEM). Conductivity measurements were carried out by the four-probe technique.