Synthesis of advanced multifunctional biopolymeric membrane via emulsion templating method

Abstract

A cost effective and reproducible method for preparing free standing porous hydrophilic biopolymeric membranes is reported in this study. Silver nanoparticles (AgNp) impregnated micropourous alginate-chitosan crosslinked biopolymeric membranes were prepared by the emulsion templating method. The instantaneous gelation of sodium alginate in the presence of Ca+2 ions enabled the liquid paraffin droplets in the initial emulsion to be settled quickly and thus aided in the pore generating process. Prisitne Alginate membrane, Alginate-Chitosan blended membrane (Alg-Ch), nanopraticle incorporated Alginate membrane (Alg-AgNp) and silver nanoparticle impregnated alginate-chitosan membrane (Alg-Ch-AgNp) were synthesized with as well as without templates, so as to compare their feasibility. On extraction of the templates, pore size corresponding to the original emulsion droplet sizes was obtained. All the variety of membranes synthesized was characterized by SEM, TGA/DTA and swelling studies. The emulsion templating method introduced micropores in the membrane morphology within the range of 100 nm–2 μm as compared to the non template alginate membranes. The decomposition of Alg-Ch-AgNp starts from 225 °C and terminates at around 328 °C with a weight loss of about 27.09 %. Alg-Ch membrane which lost about 34.385 % of its weight, showed less thermal stability than Alg-AgNp and Alg-Ch-Ag Np membranes. The swelling of Alg-Ch-AgNp membrane was about 52 % in acidic environment, 160 % in neutral environment and around 180 % in acidic environment. The results prove that Alg-Ch-AgNp is thermally the most stable and also having the best swelling characteristics among all.