writer：Yongqi Yang, Lin Guan, Guanghui Gao*
keywords：hydrogels, photochromism, flexible devices, patterning, memory devices
source：期刊
specific source：ACS Applied Materials & Interfaces
Issue time：2018年
Traditional optoelectronic devices without stretchable performance could be limited for substrates with irregular shape. Therefore, it is urgent to explore a new generation of flexible, stretchable and low-cost intelligent vehicles as visual display and storage devices, such as hydrogels. In the investigation, a novel photochromic hydrogel was developed by introducing negatively charged ammonium molybdate as a photochromic unit into polyacrylamide via ionic and covalent crosslinking. The hydrogel exhibited excellent properties of low cost, easy preparation, stretchable deformation, fatigue-resistance, high transparence, and second order response to external signals. Moreover, the photochromic and fading process of hydrogels could be precisely controlled and repeated under the irradiation of UV light and exposure of oxygen at different time and temperature. The photochromic hydrogel could be considered applied for artificial intelligence system, wearable health care device, and flexible memory device. Therefore, the strategy for designing a soft photochromic material would open a new direction to manufacture flexible and stretchable devices.