Key Words:conducting polymers; membranes; phase diagrams; phase separation
Abstract:Microporous membranes were prepared from polyaniline-diluent systems by exploiting the thermally induced phase separation, using three polymer concentrations, two quenching temperatures, and different extraction conditions. Both binodal and spinodal curves of polyaniline-diluent systems were determined by differential scanning calorimetry. The membrane morphology was determined by scanning electron microscopy and optical microscopy. Phase separation may be carried out by nucleation and growth mechanism under the conditions used in this study. A closed cell structure was obtained for the PANI-concentrated samples. In contrast, an open structure composed of strings of small beads resulted for the PANI-dilute samples. It was also found that the membrane morphology varied with the extraction temperature and extractants. A great effect of coarsening, attributed to the extremely low molecular weight of PANI and mild quenching temperature, gave large pores in the final membrane structure.
Volume:60
Issue:9
Translation or Not:no