A sensor system for detecting the presence of a target analyte. The system comprises a first conductor, a second conductor, and a sensor film. The sensor film is positioned between the first conductor and the second conductor. The sensor film includes a crosslinked siloxane polymer comprising a monomer having a hydrocarbon side group. The sensor film has an absorptive affinity for the target analyte. The electrical capacitance of the sensor system changes upon absorption of the target analyte by the sensor film.