A research team led by Associate Professor Hong-Ren Jiang from the Institute of Applied Mechanics at National Taiwan University has published research in journal Soft Matter, successfully developing novel semi-interpenetrating network hydrogels for energy-efficient smart window systems. Using a simple diffusion method, the team incorporated poly(N-isopropylacrylamide) into agarose matrices, creating composite materials with exceptional optical and mechanical properties.
This new material achieves 90% visible light transmittance at room temperature and transitions from transparent to opaque when temperature exceeds 32.1°C. Unlike conventional materials with 80-90% volume shrinkage, the new material shrinks only approximately 12% while agarose provides structural support that significantly improves mechanical properties. Research team addressed critical issues of severe volume shrinkage and poor mechanical stability in traditional thermoresponsive materials through a semi-interpenetrating network structure where agarose serves as the structural framework and PNIPAAm provides temperature responsiveness, achieving perfect synergy between functionality and stability.
The material was integrated into a glass-polymer-glass sandwich structure successfully demonstrating smart window temperature control functionality. Experiments showed these smart windows maintain high transparency at low temperatures ensuring excellent daylighting performance, automatically become opaque at high temperatures effectively blocking solar heat, and demonstrate stable reliable performance through heating-cooling cycles. Unlike electrochromic technologies requiring continuous electrical power, these hydrogel smart windows autonomously respond to environmental temperature changes achieving passive thermal management, opening new possibilities for building energy conservation technologies.in harsh environments.
Soft Matter
Agarose/PNIPAAm semi-interpenetrating network hydrogels with enhanced mechanical and optical properties for thermoregulating smart windows
https://pubs.rsc.org/en/content/articlehtml/2025/sm/d5sm00707k