Development of conductive molecularly imprinted polymers (cMIPs) for limonene to improve and interconnect QCM and chemiresistor sensing

Abstract

This paper presents a straightforward method to develop a chemiresistor based sensor for the detection of the plant volatile R-(+)-limonene. By using blends of polystyrene-based molecularly imprinted polymers (MIPs) and the organic semiconductor poly3-hexylthiophene (P3HT), electrical conductivity is introduced into the highly selective MIPs, allowing their application as sensing layers in robust and economic chemiresistor devices. Polystyrene-based MIPs and conductive blends were assessed on quartz crystal microbalances (QCMs) and chemiresistors and compared to non-imprinted polymer (NIP) and pristine P3HT layers. Blending MIPs and conductive polymers led to a strong signal enhancement, both on the QCM as well as during resistive measurements, allowing for detecting R-(+)-limonene gas concentrations as low as 50 ppm. The presented results provide a simple and valuable way for potential MIP sensing improvements and the possibility for a method transfer to cheap and simple chemiresistors.