Growth of ZnO nanorods on biodegradable poly (lactic acid) (PLA) substrates by low temperature solution method

Abstract

Plastic materials have found in every aspect of our daily life and the accumulation of plastics in the environment has led to great threat to the planet. Therefore, need for development of biodegradable plastics is essential to replace the petroleum based plastics. In this report, Zinc oxide (ZnO) nanorods were grown on the bio-degradable poly(lactic) acid (PLA) substrates for the first time by using low-temperature solution growth method. Growth of nanorods was carried out on two types of substrates; one is pure PLA substrate and the other one is PLA mixed with ZnO powder. Pure PLA substrates and ZnO powder mixed PLA substrates were prepared by the film casting method. ZnO nanorods growth was carried at different growth temperatures ranging from 50 to 90 C for the growth duration of 4 hours on both types of substrates. Nanorods growth was observed on the pure PLA substrates with very low density whereas dense nanorods growth was observed on ZnO powder mixed PLA substrates. It was concluded that at a growth temperature of 70 C, good density and aspect ratio was observed for ZnO nanorods. Absence of ZnO nanorods growth at lower growth temperature is limited by insufficient thermal energy for the decomposition of HMTA and ZnO crystallization. The ZnO nanorods growth is limited by PLA glass transition temperature at higher growth temperatures. The present results will be useful in the preparation of environment friendly active food packaging material with antibacterial properties.