Study On The Preparation, Characterization And Performance Of PAn Composite Membrane

The attraction of using conducting polymers as membrane materials is their inherent conductivity, reversible redox, electro-active properties. Thus they represent a new generation of functional membrane materials with adaptive properties that may respond to the environment or external stimulation. In addition, it may be possible to make conducting polymer based membranes with tailored molecular architecture for specific selectivity that is responsive to external signals. Among many conducting polymers, because of lots of excellent characteristics superior to those of other conducting polymers, Polyaniline was chosen to be the objective of this research project. The first part of this paper presents the method of chemical synthesis of PAn/CA composite membrane by in-situ permeation. The in-situ synthesis of conducting composite membranes of polyaniline (PAn) with commerical microporous cellulose acetate (CA) was described here. In addition, the influences of different polymerization conditions on the conductivity and apparent selectivity (CO2/O2) of PAn/CA composite membrane were studied and the optimum polymerization conditions were obtained. In the second part of this paper, the pore size and distribution of the PAn/CA composite membrane was evaluated by the method based on bubble pressure and liquid permeation, which indicated that resulting composite membrane posseses smaller average pore radius and more narrow pore distribution than that of CA host membrane. Surface and cross-sectional morphology of PAn/CA composite membrane was studied by SEM and the conducting performance was examined by measuring the range of conductivity distribution. In addition, the mechanism of composition was also described by analysis the FT-IR spectra of PAn, PAn/CA composite membrane, CA host membrane.The result of characterizing membranes microphology showed that PAn/CA composite membrane's pore structures were better than those of CA host membrane. By using the method of chemical synthesis, in-situ manipulation of membranes' microphology could be realized efficiently. Furthermore, the theoretical and experimental groundwork can also be established by a full understanding of the conductive composite membrane using in the technique of recognition and manipulation in the level of molecule.