Molecules of synthesized phthalocyanine as a material for the detection of 2,4-toluene diisocyanate (TDI)

Various numbers of LB monolayers of a metal-free phthalocyanine derivative, A410H₂Pc, have been deposited onto ultrasonically cleaned quartz substrates with platinum interdigitated electrodes. Similar devices i.e. those with the same number of LB layers, show the same response characteristics in the presence of 35 ppb (0.035 ppm) toluene diisocyanate (TDI)—a toxic substance used in the production of plastics and found in certain types of paint. The response times of the LB devices studied so far have been calculated to be about 40s. The electrical properties of evaporated films of a metal-free phthalocyanine derivative, α-H₂Pc, and those of the A410H₂Pc LB films have been found to be similar. The response time for the evaporated films has been found to be much less that that for the LB films. Although a direct comparison cannot be made between the LB and evaporated films, in this case, results suggest that devices fabricated from evaporated films will be much faster at detecting the presence of TDI than devices fabricated from LB films.