Spin-coated films of calix[4]resorcinarenes as sensors for chlorinated solvent vapours

Spun thin films were fabricated using two different calix[4]resorcinarene materials. SPR curves of the calix[4]resorcinarenes along with an uncoated gold layer were determined. Exposure of the calix[4]resorcinarene films to organic vapours led to their adsorption into the thin film with concurrent changes in film thickness and refractive index which caused shifts in the SPR curves. Kinetic graphs were obtained as a result of the repeated exposure of the film to 20–40–60–80–100% of saturated vapour for up to seven cycles. Chloroform, dichloromethane, carbon tetrachloride and trichloroethylene vapours were all utilised for the gas exposures and kinetic curves obtained for each compound. Differences in the film nature and adsorption properties are discussed. Differences in vapour adsorption were noted, with the calix[4]resorcinarenes being most effective at binding chloroform.