Molecularly imprinted polymer-Ag2S nanoparticle composites for sensing volatile organics

Polyurethane-based molecularly imprinted polymers (MIP) and Ag2S nanoparticles (NP) form a nanocomposite that is suitable for detecting vapours of aliphatic alcohols with quartz crystal microbalance (QCM) sensors. The resulting sensor responses are almost three times higher than the average response of its two constituents: the composite leads to a normalized response of 70 Hz towards 400 ppm 1-butanol vapour in air, which is two times more than for a pure NP layer of the same thickness and four times higher than the response of the MIP. Furthermore, the MIP leads to structural selectivity that strongly prefers 1-butanol over 2-butanol due to the branched structure of the latter. Selectivity reaches a factor of almost five.