Highly Efficient Photochromic Tungsten Oxide@PNIPAM Composite Spheres with a Fast Response

Abstract

Coloration efficiency and a fast response are important in developing materials for optical switching. A novel, highly efficient photochromic tungsten oxide@poly­(N-isopropylacrylamide) (PNIPAM) hybrid sphere is reported, whose colors can be rapidly converted between yellow and blue under different lights. The color change can be seen clearly even if the tungsten oxide content in the hybrid sphere is very low, exhibiting outstanding coloration efficiency of tungsten oxide. A photochromic mechanism is proposed in which the amide group in PNIPAM spheres participates in electron injection and the transition of valence states between W5+ and W6+ in the photochromic process. The interaction between tungsten oxide and PNIPAM plays a key role in enhancing the coloration efficiency of tungsten oxide and accelerating the switchable speed of color transformation, which is very useful in developing new photochromic materials. These hybrid spheres can be used in rewritable record displays and have wide potential applications in controlling energy transmittance in smart windows or in detecting UV light in optical sensors.

Advances in Electrochemical Energy Devices Constructed with Tungsten Oxide-Based Nanomaterials

“…Wei et al [189] indicated intrinsic WO 3 with color change between yellow and blue when exposed to UV illumination. Zhang et al [190] also synthesized tungsten oxide@poly(N-isopropylacrylamide) composite spheres that had excellent response speed and impressed coloration efficiency. Finally, Wang et al [191] have a comprehensive review about tungsten oxidesbased photochromic materials.…”

An injectable thermosensitive hydrogel with a self-assembled peptide coupled with an antimicrobial peptide for enhanced wound healing

“…12 PNIPAM is a traditional thermo-sensitive polymer material composed of hydrophilic amide and hydrophobic isopropyl groups, which has a low critical solution temperature (LCST) of 32-34 1C. [13][14][15] Due to this, it is possible to design a PNIPAM hydrogel containing biomolecules like growth factors, drugs, and others molecules to achieve drug delivery. 3,16 Previous research on the MGF E peptide showed regulation of the tissue repair process by promoting the proliferation of human cells, such as EA.…”

Sunlight-Responsive Titania–Hydrated Tungsten Oxide Heteronanoparticles/Paper-Based Color-Switching Film for Solar Ultraviolet Radiation Monitors

“…Cai et al designed a paper-based UV photodetector by combining a photochromic phosphomolybdic acid/citric acid system with two-dimensional (2D) Sr 2 Nb 3 O 10 and ZnO nanoparticles . Tungsten oxide nanomaterials are reported to possess rapid color-switching properties under UV irradiation, , providing an alternative for solar UV radiation monitors. We have recently reported photoreductive titania/hydrated tungsten oxide (THTO) heteronanoparticles, which exhibit a super outstanding photoreversible color-switching property under UV irradiation .…”