Amphiphilic silver-delaminated clay nanohybrids and their composites with polyurethane: physico-chemical and biological evaluations

Abstract

Silver nanoparticles (AgNPs) exhibit size-dependent bactericidal activity. They are, however, subject to aggregation when added to most hydrophobic polymers. In this study, a surfactant-modified delaminated clay (surfactant-capped nanosilicate platelets, or “NSQ”) was employed to be a nanocarrier for AgNPs. The nanohybrid of AgNPs and NSQ (“AgNP/NSQ”) in aqueous solution showed remarkable bactericidal effect as well as negligible cytotoxicity and immune response at a concentration of 10 ppm. Poly(carbonate)urethane (PCU) with different hard/soft segment ratios was synthesized and used in the preparation of the nanocomposites, PCU-AgNP/NSQ. Based on TEM observation, AgNP/NSQ was well dispersed in the resulting nanocomposites. The reinforcing effects of AgNP/NSQ in nanocomposites were distinct for PCU with different hard/soft segment ratios. The phase-separated structure of PCU-AgNP/NSQ nanocomposites was investigated by small-angle X-ray scattering (SAXS). PCU-AgNP/NSQ containing 75 ppm of Ag demonstrated superior microbiostatic effect, as well as better biodurability and lower foreign body reaction than the commercial Pellethane 2363-80A.