Synthesis of high capacity chitosan nanofiber mats catalyst platforms by electrospinning

This study describes the experimental parameters to synthesize a microns long non-woven mesh of 300--400 nm diameter nanofibers of biopolymer chitosan from an aqueous acetic acid solution. Also described is the ability of substrate-supported chitosan nanofibers, to form complexes with noble metal ions that have potential for use in catalysis. Metal-free and metal chelated chitosan nanofibers electrospun on aluminum substrates were characterized by FE-SEM. Electrospinning of chitosan in aqueous acetic acid was difficult to synthesize nanofibers. Therefore, in order to increase its processability, effects of blending it with glutaraldehyde (GA) and polyethylene oxide (PEO) were studied. The optimum blend was achieved by mixing 10 parts of a 3wt% chitosan in 90% acetic acid with 1 part of a 4wt% polyethylene oxide (PEO) in aqueous solution. This mixture was then successfully co-electrospun with a palladium precursor (Na2PdCl4) solution in a sodium phosphate buffer to obtain uniform Pd2+/--sorbed chitosan nanofiber mats. The electrospinning parameters, such as solution concentration, flow rate, voltage, and tip to collector distance, were evaluated to form uniform mats. Finally, Pd2+-sorbed chitosan nanofiber mats were stabilized on aluminum substrate (i.e., fixed or made insoluble) when exposed to an aqueous NaHCO3 buffer (pH=10). This study demonstrates that the electrospinning technique can be used to successfully synthesize high capacity Pd2+-sorbed chitosan nanofiber mats, which can be used for catalysis applications.