Effect of solution parameters on pH-response of polyacrylic acid grafted polyimide smart membrane fabricated using 248 nm krypton fluoride excimer laser

Abstract

A fast, efficient, and simple method for fabricating a pH-responsive gating membrane is discussed in this paper. 248 nm KrF excimer laser was used to fabricate base polyimide (PI) membrane and in the second stage, i.e., grafting. We have already studied the effect of laser parameters on grafting. This paper is an extension of our previous study. In this paper we reported the effects of solution parameters, i.e., concentration of monomer and crosslinker on water permeability, and diffusion across the membrane was studied. Polyacrylic acid (PAAc) was used to make membrane stimuli responsive. Caffeine was used as a model drug molecule for diffusion studies. Qualitative and quantitative analyses were carried out using ATR-FTIR and TGA methods. With the help of appropriate tuning of concentration parameters and laser parameter - the number of pulses, water permeability up to 6 order of magnitude could be achieved. We have also successfully demonstrated that controlled release of solute over a larger period could be achieved using the fabrication technique we proposed. This technique can be a powerful tool to develop responsive membranes for medical applications as the fabrication process does not involve any organic solvent.