Electropolymerized Molecularly Imprinted Polymers as Receptor Layers in Capacitive Chemical Sensors

TLDR

This study presents the first use of molecularly imprinted polymers in capacitive chemical sensors. The sensor was built by electropolymerizing phenol on gold electrodes in the presence of phenylalanine, adding a mercaptophenol self‑assembled monolayer to suppress leakage, coating with alkanethiol, and then removing the template, with impedance spectroscopy confirming the insulating properties. The multilayer sensor showed a capacitance decrease upon phenylalanine addition and negligible response to other amino acids and phenol.

Abstract

The first application of molecularly imprinted polymers to chemical sensors with capacitive detection is described. The sensitive layer was prepared by electropolymerization of phenol on gold electrodes in the presence of the template (phenylalanine). The insulating properties of the polymer layer were studied by electrochemical impedance spectroscopy. Electrical leakages through the polymer layer were suppressed by deposition of a self-assembled monolayer of mercaptophenol before polymerization and of alkanethiol after polymerization. At the final stage of sensor preparation, the template was removed. The multilayer system obtained displayed a decrease in electrical capacitance on addition of phenylalanine. Only a low response was observed toward other amino acids and phenol.