Influence of pore diameter on physical and sensing properties of free-standing Chitosan-Silica Nanocomposite membrane

In this work, we have observed change in different physical properties and glucose sensing capability of Chitosan-Silica nanoparticle composite membranes (CSNCM) with pore diameter variation. For a particular mixture percentage of chitosan and SiNp dust, successful fabrication of deformation free, free-standing membrane formation was possible. Silica nanoparticles of three different sizes (NP1 ~ 100 nm, NP2 ~ 300 nm & NP3 ~ 500 nm) were prepared to produce CSNCM of corresponding pore sizes (CM1, CM2 and CM3 respectively). Hot NaOH etching was performed to induce surface pore in CSNCM matrix by dissolving Silica nanoparticles from the top layer. We have found that pore distribution, surface morphology, optical properties and dielectric properties are very much dependent on pore size of the membranes. For glucose sensing characterization, we have focussed on multi-parametric optical sensitivity of the membranes in presence of glucose molecules and found that, though all three membranes show response in one or more parameters, only CM2 membranes hold the capability to perform as a multi-parametric sensor in our optical sensing arrangement.