Fabrication of PEG‐anthracene/alginate double‐network hydrogels and their application in photolithography.

The development of double‐network hydrogels provides a feasible strategy to improve the mechanical properties of pure organic hydrogels. We report a new type of dynamic double‐network hydrogels based on alginate and four‐armed PEG bearing anthracene at the terminal group. The ductile network is constructed through the photopolymerization of four‐armed PEG‐anthracene using the dimerization of terminal anthracene as the cross‐linking point, and alginate as the brittle network. The doping of alginate improves the precursor viscosity of solution and slows its fluidity. In particular, the inclusive metal cations endow the hydrogels with good conductivity. As the demonstration toward photolithography, the letter patterns and a parallel circuit are fabricated through the mask exposure method. By employing selective photo‐crosslinking, their shapes and patterns can be precisely controlled. Owing to the photo‐responsive features of the PEG‐anthracene network, the hydrogels also behave dynamically mechanical and shape‐memory properties via switching the irradiation wavelength. In addition, the water retention capacity can be improved by adding glycerol. This work demonstrates that anthracene is an effective photopolymerization unit in constructing dynamic double‐network hydrogels that show potential applications in smart soft materials. [ABSTRACT FROM AUTHOR]