CdSe nanodots to nanorods in PVA films: effect of shape transition and loading on the opto-mechanical and biodegradation properties

Polyvinyl alcohol (PVA) films impregnated with CdSe nanoparticles were evaluated for the effect of morphology (from spherical to rod-shaped) and concentration of CdSe, on the optical and mechanical properties. CdSe nanodots and nanorods were synthesized by a modified microemulsion method with hydrazine hydrate as the shape modulator. CdSe nanoparticles and PVA/CdSe films were characterized by high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-Vis spectroscopy and universal testing machine (UTM) analysis. The tensile strength and % elongation (at break) of PVA/CdSe films, increased from 32.8 MPa and 178 % (for CdSe nanorods) to 40.3 MPa and 259 % (for CdSe nanodots), respectively. The effect of loading of CdSe in PVA films, were evaluated at 0.1, 0.5, 1.0, 5.0 and 10 wt%. The tensile strength increased from 18.9 MPa (plain PVA) to 35.08 MPa (1 % CdSe) and increased upto 40 MPa for 10 % CdSe. The absorbance of PVA/CdSe films increased, while the reflectance and the transmittance decreased, with increasing wt% of CdSe in PVA films. The colour, density and water-vapour permeability of PVA/CdSe films, were also estimated. The biodegradability of PVA/CdSe films in soil was found to increase by 55 % as compared with PVA films.