writer：He, Q (He, Qiang) [1] ; Wang, YJ (Wang, Yongjuan) [1] ; Zhou, YM (Zhou, Yuming) [1] , [2] ; He, M (H
keywords：Smart windowThermochromic hydrogelSolar modulationEnergy saving
source：期刊
Issue time：2019年
Passively responsive thermochromic smart window, which can modulate indoor incident solar light automatically at relatively high outdoor temperature, is a practical energy-saving device for construction and automotive industries. In this paper, a thermochromic composite hydrogel film based on W-doped vanadium dioxide (W-VO2), poly N-isopropyl acrylamide (PNIPAM) and polyacrylamide (PAM) is presented and this hydrogel film was prepared between two quartz substrates to form the sandwich structured smart window. In this thermochromic system, 2 wt% monoclinic W-VO2 were dispersed in the hydrogel film with the thickness of 0.1 mm. The introduction of PAM changes the flow-state PNIPAM microgel to hydrogel, which dramatically improved the practicality of the PNIPAM-based smart window. When the outdoor temperature is higher than 40 degrees C, the solar modulation capacity of this passive smart window, with a high luminous transmittance of 72% at 25 degrees C, can reach 46.3%, The smart window possesses high solar modulation ability and more than 20% luminous transmittance even after 40 times high temperature durability tests.