Photoluminescent and photochromic smart window from recycled polyester reinforced with cellulose nanocrystals

Abstract

Smart windows with long-persistent phosphorescence, ultraviolet (UV) light protection, high transparency, and high rigidity were developed by easily immobilizing varying ratios of lanthanide-activated aluminate phosphor nanoscale particles within a composite of recycled polyester/cellulose nanocrystals (RPET/CNC). Cellulose nanocrystals were prepared from rice straw waste. Cellulose nanocrystals were used at low concentration as both crosslinker and drier to improve both transparency and hardness. The phosphor nanoscale particles must be distributed into the recycled polyester/cellulose nanocrystals composite bulk without agglomeration to produce transparent RPET/CNC substrates. Photoluminescence characteristics were also studied using spectroscopic profiles of excitation/emission and decay/lifetime. The hardness efficiency was also examined. This transparent recycled polyester waste/ cellulose nanocrystals nanocomposite smart window has been shown to change colour under UV light to strong green and to greenish-yellow when it is dark, as proved by Commission Internationale de l'éclairage (CIE) laboratory colour parameters. It was found that the afterglow RPET/CNC smart window had phosphorescence intensities of 428, 493, and 523 nm upon excitation at 368 nm. There was evidence of improved UV shielding, photostability, and hydrophobic activity. In the presence of a low phosphor ratio, the luminescent RPET/CNC substrates showed quick and reversible fluorescence photochromic activity when exposed to UV radiation.

Thermochromic Energy Efficient Windows: Fundamentals, Recent Advances, and Perspectives

“…Photochromic materials can automatically modulate sunlight by environmental photostimulation and have gained important attention in smart windows. − The rate of color transition of thermochromic hydrogel smart windows is relatively slow due to ambient temperature changes. Adding photothermochromic materials to the smart window based on hydrogels can overcome this delayed response .…”

Synthesis and molecular docking of novel fluorescent alkoxy‐substituted iodobiphenyl analogues

“…Photoresponsive compounds can change their physical and/or chemical features upon exposure to light [22][23][24][25][26][27][28][29][30][31][32][33]. Here, different organic solvents were used to examine both the absorbance and fluorescence activities of the synthesized iodobiphenyl ethers, as summarized in Table 1.…”

Development of photoluminescent viscose fibers integrated with polymer containing lanthanide‐doped phosphor

“…Conversely, coated clothing with pigment concentrations over 6% produces an afterglow effect, leading to a slower reversibility. The causing a color change to greenish-yellow that can be undone by removing the UV irradiation effect and returning to its original white hue (Abdu et al, 2023;Al-Balakocy et al, 2022).…”