Optical Sensor Based On Ultra Thin Film of d-Form Syndiotactic Polystyrene for Fast and High Resolution VOCs Detection

The performances of an optoelectronic sensor was analyzed, which was based on a sensitive nanoscale film of semicryst. syndiotactic polystyrene (sPS) with a nanoporous cryst. phase developed for fast and high resoln. detection of chloroform. In particular, the change of the polymer refractive index due to chloroform sorption into the polymer layer when the sensor is exposed to CHCl3 has been used as transduction property. Reflectance measurements have been performed using a fiber optic refractometer, coated with nanometric sPS film at very low pressure of chloroform, demonstrating high sensitivity and fast-time response combined with excellent reversibility. Mass sorption expts. have also been performed on the same polymeric material with an electronic microbalance at the same conditions at which the optical sensor has been characterized. This allowed a quant. correlation between the mass of the analyte sorbed within the polymer layer and the refractive index variation, which has been found to be essentially independent of the temp.