posted on 2021-08-10, 12:42authored byJunwen Deng, Hangrui Wu, Wendi Xie, Haoyuan Jia, Zhonggang Xia, Huiliang Wang
Fluorescent
polymeric hydrogels especially multicolor fluorescent
polymeric hydrogels (MFPHs) have important applications in information
storage, encryption, and encoding. MFPHs are generally prepared by
incorporating multiple traditional fluorescent materials into hydrogels.
In recent years, nontraditional luminescent polymers without any traditional
π-conjugated chromophores have received increasing attention.
Here, we report a novel type of nontraditional MFPHs prepared by in
situ polymerization of acrylamide (AAm) in the presence of poly(itaconic
acid) (PITAc). The hydrogen-bonded mechanically strong PAAm/PITAc
hydrogels show strong intrinsic fluorescence, and the fluorescence
emission is excitation-dependent and metal cation-responsive. More
impressively, the hydrogels treated with metal cations also possess
excitation-dependent fluorescence. We developed a multi-ion inkjet
printing (MIIP) technique to print texts or designed patterns onto
the hydrogel surface using different metal cation solutions as inks,
and then variable texts or patterns appear under the irradiation of
UV, violet, and blue lights. Patterns can be further changed by selective
printing, erasing, or reprinting on some regions. Therefore, multidimensional
information encryption is achieved. This work provides a new strategy
for preparing MFPHs for wide applications.