An investigation of the feasibility of using sol-gel derived thin films toward development of optical sensors.

摘要

A variety of porous optically transparent titanium alkoxide carboxylate films that can be supported on silicate glass substrates have been developed. These films were made by spin casting intermediate polymeric solutions of alkoxide carboxylates processed using sol-gel techniques. A variety of appropriate probe molecules can be entrapped or immobilized within the porous polymer matrix of these films. These porous films, being optically transparent and having the capability to host probe molecules, provided an excellent system to investigate the possibility of making optical sensors. As a model system we picked a colorimetric reagent, Fe(III) porphyrin, as the probe molecule to detect free cyanide ion concentrations in aqueous solutions. Chemically induced structural modifications of the polymer were carried out to stabilize the encapsulated metalloporphyrin. An optical parameter reflective of the chemical changes that occur in the system was selected as the measurement tool and its calibration was linear over the cyanide ion concentration range of 40 ppm to 25,000 ppm. (Abstract shortened by UMI.).