Functionalized polysiloxane thin films deposited by matrix-assisted pulsed laser evaporation for advanced chemical sensor applications

High-quality thin films of fragile chemoselective polymers with precise and accurate thickness, density and chemical integrity are required for advanced chemical sensor applications. While these attributes are difficult to achieve by conventional methods, we have successfully demonstrated the matrix-assisted pulsed laser evaporation (MAPLE) deposition of thin films of especially synthesized fluoro-alcohol substituted carbopolysiloxane polymer coatings. The quadrupled output of a Nd:YAG laser (265 nm) served as the laser source and depositions were done in a background pressure of N2. Using various solvents appropriate to solvate this polymer (e.g. tetrahydrofuran, acetone and chloroform) and varying the laser fluence, we optimized the deposition of high-quality thin films on 1 cm2 double-polished silicon substrates. The best solvent used as matrix was proved to be acetone. Under these conditions, the important functional groups were reproduced and observed by Fourier Transform Infrared Spectroscopy (FTIR) as compared to the drop cast films and the surface roughness was analysed using Atomic Force Microscopy (AFM) and found to be much smoother than conventional wet deposition techniques.