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A Phase‐Changing Polymer Film for Broadband Smart Window Applications
Author(s) -
Xie Yu,
Guan Fangyi,
Li Zhou,
Meng Yuan,
Cheng Jiang,
Li Lu,
Pei Qibing
Publication year - 2020
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202000290
Subject(s) - materials science , crystallinity , amorphous solid , polymer , transmittance , opacity , acrylate , phase (matter) , chemical engineering , thermochromism , glazing , polymer chemistry , copolymer , optoelectronics , composite material , optics , organic chemistry , chemistry , physics , engineering
Smart windows (SWs) with tunable opacity are sought to regulate solar‐irradiation and privacy protection. A new smart window material based on a phase‐changing polymer that can be reversibly switched between a semicrystalline, opaque state and an amorphous, transparent state is introduced. The polymer film is a network of the phase‐changing poly(stearyl acrylate) crosslinked with a poly(ethylene oxide) oligomer. The two constituent polymers show strong phase separation. The transmission switching of the resulting copolymer film is resulted from the combination of three different mechanisms: reversible phase changing of the poly(stearyl acrylate) component, phase separation between the two distinct constituent polymers, and a large change of refractive index of the phase‐changing polymer during the amorphous‐to‐semicrystalline transition. The opaqueness switching can be reversed and repeated for more than 500 cycles of heating and cooling. A silver nanowire (AgNW)‐based transparent heater is combined with the SW film to control the semicrystalline‐to‐amorphous phase transition. The resulting smart window exhibits a high infrared transmittance modulation (Δ T IR ) of 80.4% and solar transmittance modulation (Δ T solar ) of 70.2%, which significantly outperform existing thermochromic smart windows.