Surface Modification and Dielectric Response Investigation of Cellulose Acetate Membrane Treated by ArF Excimer Laser

Abstract

Lasers are used to modify the surface morphology, crystallinity, chemical composition, reactivity and resistivity of polymer surfaces. In this work, several cellulose acetate membranes were exposed by ArF excimer laser, 193 nm, at 2 - 20 UV pulses, with 100 - 350 mJ/pulse energy, at 1 Hz pulse repetition rate. Characterization techniques viz. Fourier transform infra-red spectroscopy (FTIR), Contact angle measurement, Scanning electron microscopy (SEM), Atomic force microscopy (AFM) with roughness analysis, Water Flux measurement was exploited to understand the induced changes in the surface properties of the polymer. The contact angle measurement was done here, to determine hydrophilicity of the irradiated polymer at various doses. The frequency dependent dielectric behavior was studied both in reference and irradiated samples in the frequency range from 75 KHz - 30 MHz. Results showed that the morphological surface changes with laser irradiation, and the water contact angle alters as the surface of the membrane is modified.