Microstructuring conducting polymers and molecularly imprinted polymers by light-activated electropolymerization on micromachined silicon. Applications in electrochemical sensing

Abstract

Light-activated electropolymerization on micromachined n-type silicon is here demonstrated to be a versatile route for microstructuring conducting polymers (CPs) and CP-based Molecularly Imprinted Polymers (MIPs). Several CPs - namely polypyrrole (PPy), poly(3,4-ethylendioxythiophene) (PEDOT), poly(3-methylthiophene) (P3MT), polythiophene (PT) - and a PPy-based MIP have been deposited on different microstructured n-type silicon templates featuring ordered-array of pores with variable aspect-ratio (AR) between 1 and 10. CP and MIP microtubes with size of a few micrometers, height from 5 up to 50 micrometers, and period of a few micrometers are successfully synthesized by replication of the silicon template features with submicrometer accuracy, as demonstrated by scanning electron microscopy (SEM). A significant electroactivity increase is observed for CP microtubes thanks to the augmented surface of microstructured films, as highlighted by cyclic voltammetry (CV), thus demonstrating that the entire microstructured polymer surface is effectively involved in electrochemical redox processes. PPy-based MIPs for the antibiotic sulfadimethoxine (SDM) exhibit good sensing properties in SDM electrochemical detection, with current responses notably higher than Not-Imprinted Polymers (NIPs). A significant current response increase on microstructured MIPs with respect to the flat ones is also verified.