Polymer stabilized cholesteric liquid crystal arrays for detecting vaporous amines

In this paper, we report the utility of a colorimetric polymer stabilized cholesteric liquid crystal (PSCLC) array for detecting vaporous amines. The PSCLC with various polymer concentrations (5-20% w/w) is made into an array which shows distinct color changes upon exposure to 400 parts-permillion (ppm) octylamine vapor at 23-35 degrees C. Interestingly, PSCLC shows stronger response to primary amine over secondary amine, tertiary amine, ester, aldehyde, and alkane having similar molecular weights. PSCLCs also give detection limits as low as 2 ppmv for decylamine. Because PSCLC is transparent at room temperature and changes color upon exposure to amine vapors, it can be coated on windows or safety goggles to offer protection against amine vapors.