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A Phase-Changing Polymer Film for Broadband Smart Window Applications
Yu Xie1, Fangyi Guan1,2, Zhou Li1
1Department of Materials Science and Engineering, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, CA, 90095, USA.
Macromolecular Rapid Communications
|July 22, 2020
Summary
A novel smart window material switches opacity using a phase-changing polymer, offering tunable light and privacy control. This advanced material demonstrates high performance and durability for energy-efficient buildings.
Area of Science:
- Materials Science
- Polymer Chemistry
- Optoelectronics
Background:
- Smart windows (SWs) are crucial for regulating solar irradiation and enhancing privacy.
- Existing thermochromic smart windows have limitations in performance and efficiency.
Purpose of the Study:
- Introduce a new smart window material based on a phase-changing polymer.
- Investigate the mechanisms behind its tunable opacity and switching capabilities.
- Evaluate its performance compared to existing technologies.
Main Methods:
- Synthesized a copolymer film from poly(stearyl acrylate) and poly(ethylene oxide).
- Utilized a silver nanowire (AgNW)-based transparent heater for phase transition control.
- Characterized the film's optical and thermal switching properties.
Main Results:
- The copolymer film exhibits reversible switching between opaque and transparent states.
- Switching is driven by polymer phase change, phase separation, and refractive index variation.
- Achieved high infrared transmittance modulation (80.4%) and solar transmittance modulation (70.2%).
- Demonstrated over 500 cycles of reversible heating and cooling.
Conclusions:
- The developed phase-changing polymer smart window significantly outperforms current thermochromic SWs.
- This material offers a promising solution for energy-efficient windows with tunable optical properties.
- The combination of polymer phase transitions and phase separation provides effective opacity control.
