Polylactic acid film embedded with phosphor nanoparticles: Photochromic and afterglow biodegradable window and concrete

A smart window is a window made of a stimuli-responsive material whose transparency can be switched on and off. However, smart windows are often made of fragile, non-biodegradable and costly glass. Herein, this work presents the preparation of a transparent smart window from the environmentally-friendly polylactic acid (PLA) plastic. The plastic window was prepared by physically immobilizing nanoparticles of lanthanide-doped aluminate (NLdA; 79-112 nm) at different ratios into PLA bulk. The developed plastic showed afterglow emission, photochromism, superhydrophobicity, durability, UV shielding, rigidity, photostability, biodegradability, and excellent optical transmittance. NLdA was produced as nanoparticles to enhance NLdA dispersion in the plastic mass. NLdA must be uniformly disseminated in the PLA matrix without aggregation in order to provide transparent smart PLA window with long-persistent phosphorescence and photochromic properties. Different analytical methods were employed to determine the morphology, chemical composition, photoluminescence and coloration properties of smart films. There was an examination of the hardness characteristics. The transparent PLA window absorbed light at 365 nm and emitted at 435 nm and 517 nm, demonstrating reversible photochromism to green when irradiated with UV and greenish-yellow emission when exposed to darkness. There was a significant improvement in ultraviolet shielding and hydrophobicity upon increasing the phosphor content.