writer：Yongqi Yang, Lin Guan, Haicheng Jiang, Lijie Duan*, Guanghui Gao
keywords：photochromic hydrogel
source：期刊
specific source：Journal of Materials Chemistry C
Issue time：2018年
Ink-free printing based on photochromism has attracted great attention as a new generation of printing technology. However, the current photochromic materials are limited due to slow response and high cost. In this investigation, a rapidly responsive photochromic hydrogel with high mechanical strength was explored through the introduction of cheap ammonium molybdate into gelatin and hydrophobic association polyacrylamide. The photochromic hydrogel exhibited excellent mechanical strength of 750 kPa and rapidly responsive photochromic process with 5-second to UV light irradiation. Moreover, the hydrogel could withstand long elongation and high compressive stress with shape recovery ability. The rapid photochromic properties allowed hydrogels with fast and easy “printing” performance. More importantly, the “printed” text or pattern in hydrogels could be erased at 70 °C in oxygen environment. In addition, the hydrogel was allowed to be written in characters by using reducing reagents. The photochromic hydrogels with ink-free printing ability would demonstrate a new design strategy for soft materials with low-cost, rapid response and high mechanical properties.