Fabrication of Ag-exchanged zeolite/chitosan composites and effects of plasma treatment

Abstract

Composites made of zeolites with silver (Ag) and high molecular weight chitosan matrices were synthesized using a solvent-casting technique. XRD, ED-XRF, and FTIR results revealed the successful inclusion of Ag into the natural zeolite. Results also showed the possible redistribution of the exchangeable cations within the zeolite framework after the ion-exchange process. Plasma treatment modified the surface properties of the composites as revealed by AFM and surface free energy (SFE) calculations. Roughness increased with increasing Ag-zeolite content and increased further by at least 2.3 times after plasma exposure. Water contact angle decreased by half after treatment. SFE increased by at least 25% due to the increased contribution of the polar component after plasma treatment. This work showed that the ion-exchange method is effective in incorporating Ag into the zeolite framework and plasma treatment can tune the surface properties such as roughness and wettability. With the promising properties of the composites attributed to the biocompatibility of chitosan and zeolite, the antibacterial activity of Ag and the improved surface characteristics due to plasma treatment, the material is a suitable candidate for biomedical applications.