Development of SPR Gas Sensor for Small Molecules Using Molecularly Imprinted Polymer Thin Films

Molecularly imprinted polymer thin films were applied to develop a gas sensor based on the surface plasmon resonance phenomenon for small gaseous molecules such as toluene and xylene. The imprinted polymer films were synthesized via photo-polymerization method using various combination of templates, functional monomers and cross-linkers. The temperature of pre-polymerization solutions and the power of UV light were controlled for optimized performance of gas sensing. The morphology and porosity of the polymer films were controlled by varying the mixing ratios of the pre-polymerization solutions and confirmed by atomic force microscopy. By fitting the adsorption/desorption sensorgrams to conventional kinetic models, the effects of different templates and cross-linkers were interpreted in term of the structural differences of the polymer networks formed on the gold film. The sensitivity and selectivity of sensors were estimated for toluene and xylene, and also for humidity and other gaseous molecules such as formaldehyde and ammonia.