Design of Selective Chemical Sensor via Liquid Crystals Integrated with Organic Ionics

Abstract

Due to the combination of anisotropic nature and extraordinary sensitivity on a variety of stimuli, liquid crystals (LCs) have been widely used for design of chemical sensors. However, the relatively low selectivity to specific chemicals has prevented the realization of their full potential. Here, we propose simple and versatile design rules to control not only selectivity but also sensitivity by decorating the interface of LC films with organic ionics (OIs). We demonstrated the OI-LC sensors to selectively sense and optically report the exposure of a specific gas molecule (acetic acid) even at very low concentration (< 1 ppm). In addition, we experimentally and theoretically showed that their characteristics are precisely controllable by modulating the length of carbon chain and type of counter ion in OIs.