期刊
ADVANCED FUNCTIONAL MATERIALS
卷 30, 期 28, 页码 -出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/adfm.202000754
关键词
double networks; hydrogels; interpenetrating networks; lower critical solution temperature; whiteness
类别
资金
- ERC [742829, 679646]
- Academy of Finland (Center of Excellence HYBER)
- Flagship Programme on Photonics Research and Innovation, PREIN [320165]
- Academy of Finland [301820, 316416]
- Academy of Finland (AKA) [316416, 316416] Funding Source: Academy of Finland (AKA)
- European Research Council (ERC) [679646, 742829] Funding Source: European Research Council (ERC)
Beside pigment absorption and reflection by periodic photonic structures, natural species often use light scattering to achieve whiteness. Synthetic hydrogels offer opportunities in stimuli-responsive materials and devices; however, they are not conventionally considered as ideal materials to achieve high whiteness by scattering due to the ill-defined porosities and the low refractive index contrast between the polymer and water. Herein, a poly(N-isopropylacrylamide) hydrogel network with percolated empty channels (ch-PNIPAm) is demonstrated to possess switchable bright whiteness upon temperature changes, obtained by removing the physical agarose gel in a semi-interpenetrating network of agarose and PNIPAm. The hydrogel is highly transparent at room temperature and becomes brightly white above 35 degrees C. Compared to conventional PNIPAm, the ch-PNIPAm hydrogel exhibits 80% higher reflectance at 800 nm and 18 times faster phase transition kinetics. The nanoscopic channels in the ch-PNIPAm facilitate water diffusion upon phase transition, thus enabling the formation of smaller pores and enhanced whiteness in the gel. Furthermore, fast photothermally triggered response down to tens of milliseconds can be achieved. This unique property of the ch-PNIPAm hydrogel to efficiently scatter visible light can be potentially used for, e.g., smart windows, optical switches, and, as demonstrated in this report, thermoresponsive color displays.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据