Preparation and characterization of microporous cellulose acetate films using breath figure method by spin coating technique

This work reports the preparation and characterization of microporous cellulose triacetate films. Cellulose triacetates were obtained from homogeneous acetylation of cellulose extracted from wood by an effective method totally free of chlorine. The microporous films were produced by breath figure method by spin coating technique. In the breath figure method, the formation of the pores in the polymer films involves the phenomenon of condensation of water vapor on a polymer solution surface, so that the condensed water droplets act as a template for formation pores. The porous films were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films showed pores with rounded morphology and the pore diameter ranged from 0.1 to 0.5 µm. The effects of the solvent, concentration of the polymer solution and polymer molecular weight were investigated on the formation, morphology and size of the pores. Large porous structures are observed when lower polymer concentrations and higher molecular weight are used. Higher pore densities were observed when dichloromethane was used as solvent. The films produced could be used as biomaterials such as cell culture substrate or in sensing devices. From the results obtained in this work it is possible to predict the pore depth, size and density in cellulose triacetate films, allowing the manipulation of these parameters for future desired applications.