Effects of Water Content on Preparation and Properties of Bacterial Cellulose/Polyaniline Composite Gel-membranes

Bacterial cellulose (BC) nanogel-supported polyaniline (PANI) conducting polymer composite gel-membranes with different water contents have been synthesized via in situ polymerization of aniline onto bacterial cellulose scaffold. Preparation conditions such as water content and reaction time,were systematically employed to achieve high conductivity. The effects of water content and reaction time on the composites' properties were intensively studied. The resultant high water content bacterial cellulose/polyaniline (HBC/PANT) and low water content bacterial cellulose/polyaniline (LBC/PANI) composite gel-membranes were fully characterized in terms of structure and morphology. The morphology of HBC/PANI and LBC/PANI composite gel-membranes was observed using a field-emission gun scanning electron microscope (FE-SEM), which demonstrated the PANT were polymerized in the network of BC. Four-probe conductivity tests showed that the best reaction time was 90 min, and samples with low water contents exhibited conductivity as high as 1.72 x 10(-2) S/CM, which increased by 57. 8% compared to that of HBC/PANI, but complete drying displayed poor conductivity. Alternating-current (AC) impedance measurements proved that ionic conductivity of BC/PANT composites with lower water content was improved. The ionic conductivity of HBC/PANI is 1. 44 x 10(-4) S/cm and that of LBC/PANI is 1. 49 x 10(-4) S/cm. The mechanical property tests indicated the obtained BC/PANT composites possessed good mechanical properties, with tensile strength of 0. 21 MPa. Besides, low water content could remain good mechanical property. Furthermore, the growth mechanism of BC/PANT composite gel-membranes may be interpreted as first aniline dispersion onto BC nano-fiber network with the hydrochloric acid, and secondly in situ polymerization of aniline with oxidant ammonium persulfate (APS)