Effect of free volume on nonlinear optical characteristics of P(St-co-MMA)/CuO and PSAN/CuO polymer nanocomposites

Abstract

Microstructural dependance of nonlinear optical (NLO) properties of Poly (Styrene-co-Methylmethacrylate) (P(St-co-MMA)/Cupric Oxide (CuO) and Poly(styrene-co-Acrylonitrile) (PSAN)/CuO polymer nanocomposites (PNCs) has been explored. The positron lifetime parameter viz., free volume hole size (Vf) and NLO parameters viz., third-order nonlinear absorption coefficient (β) and nonlinear refractive index (n2)) are maximum at 0.4 wt% and 1.0 wt% of CuO nanoparticles loadings in P(St-co-MMA)/CuO and PSAN/CuO PNCs respectively. The crystallinity and optical energy band gap decreased in P(St-co-MMA)/CuO and PSAN/CuO PNCs at 0.4 wt% and 1.0 wt% of CuO nanoparticles loading respectively. The reduced optical energy band gap and the formation of bigger free volumes promote the dipole polarization and therefore the NLO properties of P(St-co-MMA)/CuO and PSAN/CuO PNCs.