Swelling behaviour of calixarene film exposed to various organic vapours by surface plasmon resonance technique

Calixarene molecules can be deposited using the Langmuir–Blodgett (LB) film technique as an active layer which can be utilised in the field of volatile organic vapour sensing applications. The sensing responses of the films against benzene, ethyl benzene, toluene and m-xylene were measured by the surface plasmon resonance (SPR) method. Fast and reversible adsorption of organic vapours could be observed. The changes in reflectivity implied the swelling behaviour of calixarene film during adsorption and can be explained by the capture of organic vapour molecules. Fick's law for early-time diffusion was adopted to quantify real time SPR data for the swelling processes. It was observed that diffusion coefficients (D) for swelling obeyed the t1/2 law and could be correlated with the various organic vapours used.