Incorporation of indolinospirooxazine on ethylene‐vinyl acetate copolymer to produce a intelligently temperature‐regulated nonwhite cool material

Abstract

Cool materials that adjust cooling efficiency according to sunlight intensity are needed because people have different needs for cooling at different times. Several colors of commercial microencapsulated photochromic powder were melt blended with ethylene-vinyl acetate copolymer in a two-roll mill at 90 C to prepare the photochromic films of corresponding colors. Pink photochromic films [the organic photochromic compound is indolinospirooxazine (NISO)] were selected to continue the following variable experiment due to its best performance in the indoor cooling test. The pink photochromic films change color as well as transmittance according to the intensity of sunlight, thereby achieving an intelligent cooling effect. A maximum decrease around 10 C was observed in natural environment when the addition amount of pink photochromic powder reaches 2.0 phr under strong sunlight and all films did not show cooling effect under weak sunlight. This material can be covered on buildings to regulate the indoor temperature.

Preparation and characterization of plasticized polyvinyl chloride composite film based on photochromic intelligent cooling

“…For the indoor sunlight simulation experiment with UV irradiation, from the graph we can see that the P/red shows the best cooling effect, and the maximum cooling amplitude is about 10 C. This is because the thermal effect of Vis light is closely related to the wavelength: the thermal effect increases with increasing wavelength. [35] Therefore, P/red, which reflects longwavelength red light, performs the optimal cooling effect. In addition, the better cooling effect of P/purple and P/black is mainly attributed to their low overall light transmittance, which makes them also have poor transmittance in the NIR region with the strong thermal effect.…”

Achieving Smart Photochromics Using Water-Processable, High-Contrast, Oxygen-Sensing, and Photoactuating Thiazolothiazole-Embedded Polymer Films

“…9 Photofluorochromism was demonstrated using cyanostilbene derivatives in poly(vinyl alcohol) (PVA) nanowire films. 6 A variety of processing conditions have been explored such as solvent-free indolinospirooxazine/ethylene-vinyl acetate copolymer or spirooxazine or spiropyran/disentangled ultrahigh-molecular-weight polyethylene in a two-roll mill, 10,11 and spiropyran-based or spirooxazinebased photochromic compounds dissolved in alcohols slot-diecoated onto poly(ethylene terephthalate) (PET) substrates. 12 There remain many critical challenges for organic photochromics, including relatively slow switching speeds, limited spectral coverage, poor reversibility, tunability, and integration with existing technologies.…”