Discrimination of Alcohol Molecules Using Hydrogen-Bridged Cholesteric Polymer Networks

This paper presents a novel hydrogen-bridged cholesteric liquid crystal (CLC) polymer networks with a porosity. This kind of material is adopted to distinguish methanol from ethanol. Because of the diversity of molecular affinities in ethanol and methanol with the hydrogen-bridged cholesteric polymer networks, the reflected colors of the cholesteric polymer networks are obviously different upon the uptake of the alcohol solutions with different ratios of methanol/ethanol. Furthermore, the composition of the monomers was altered to obtain the different sensitivities of the different alcohol concentrations and ratios of methanol/ethanol. The reduction of cross-link density and increasing amount of alkyloxybenzoic acid in polymer networks can enhance the distinguishing ability between methanol and ethanol. The function of change in transmission-valley wavelength of CLC versus the alcohol concentration and the ratio of methanol/ethanol was also obtained from the experimental results.