Three-Dimensionally Porous Polystyrene Films Fabricated via an Ultrasound Assisted Template Method

Abstract

Here a novel technique was employed to fabricated three-dimensionally porous polystyrene (PS) films via ultrasound assisted template method. In contrast to spin-coated thin film, different morphologies appeared on the films prepared by casting PS/toluene solution on glass substrates. By varying either systematic parameters or intrinsic parameters, surface structures changed from two-dimension flat pores to three-dimension sponge pores. The influences of ultrasonic intensity, frequency, irradiation time, film thickness and toluene content in water bath on surface morphologies were extensively studied. Scanning electron microscopy and white-light confocal microscopy showed that PS casted films with thickness of 200μm have a higher porosity and lower surface roughness within micrometer range. The contact angle measurement indicated slight changes of surface hydrophilicity with toluene content in water bath. Suitable toluene content favored multilayer formation of PS film and led to monodisperse pore distribution analyzed by ImageJ.