Synchrotron SAXS, XRD and FTIR Characterization of Nanostructured PVA/TEOS Hybrid Cross-Linked with Glutaraldehyde

Abstract

Polyvinyl alcohol (PVA) is a unique synthetic biocompatible polymer and it has a large number of hydroxyl groups that can react with many kinds of functional groups. In the present work, nanostructured PVA/TEOS hybrids were characterized by Small-angle X-ray Scattering (SAXS) associated with Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. We have synthesized hybrids based on the reaction of PVA with tetraethoxysilane (TEOS). PVA/TEOS hybrids were also modified in the nanometer-scale by crosslinking with glutaraldehyde (GA) during the synthesis involving hydrolysis and condensation of PVA/TEOS network. FTIR spectra showed major vibration bands associated with organic-inorganic chemical groups present in the hybrid composite PVA/TEOS. XRD coupled to FTIR results have indicated the presence of semi-crystalline domains embedded in amorphous PVA matrix. SAXS results were presented as plots with experimental scattering intensity, I(q), as a function of the modulus of the scattering vector, q. SAXS curves showed quite different trend on vector q with the scattering intensity I(q) corresponding to samples PVA, PVA/GA and PVA/TEOS/GA. Pure PVA sample showed a “knee” type curve, with maximum value q=0.04 Å-1. These results have indicated different nano-ordered disperse phases for PVA, PVA/TEOS hybrid and PVA/TEOS/GA chemically crosslinked hybrid.