posted on 2022-01-06, 01:14authored byMengda Xu, Yan Miao, Xiaxin Qiu, Xiaodong Song, Qiuhua Zhao, Jiahui Yu, Lidong Zhang
Information
camouflage and decryption on hydrogels rely on chemical
stimuli such as pH, ultraviolet light, and chemical reactions, in
which the cyclability is limited. This work develops a simpler yet
effective physical method that can achieve the information camouflage
on hydrogels by water swelling and decrypt it under white light. The
information camouflage and decryption can proceed with unlimited cycles.
To successfully reach the information camouflage, the hydrogel is
synthesized with the water swelling ratio in weight as high as 250,
which is enabled by the strong electrostatic repulsion of cationic
moieties inside the network. At such a high water-swollen state, the
hydrogel is still robust and elastic, which provides a mechanical
basis to maintain the stability of the camouflaged information. We
write information on the hydrogel surface by laser cutting. Upon immersing
the hydrogel in water, the high swelling results in huge expansion
of the hydrogel, thus inducing the information camouflage. With exposure
to white light, the information can be decrypted and becomes visible
again. Our protocol utilizes a simple physical process to enable the
camouflage and decryption of complex information, which might open
an alternative pathway for the development of hydrogel materials in
the application of informatics.