Affiliation:
1. State Key Laboratory of Bio-fibers and Eco-textiles College of Materials Science and Engineering Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological textiles Institute of Marine Biobased Materials Qingdao University Qingdao 266071 P. R. China
2. State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Fudan University Shanghai 200438 P. R. China
Abstract
AbstractHydrogel actuators with complex 3D initial shapes show numerous important applications, but it remains challenging to fabricate such actuators. This article describes a polyelectrolyte‐based strategy for modulating small‐scale internal stresses within hydrogels to construct complex actuators with tailored 3D initial shapes. Introducing polyelectrolytes into precursor solutions significantly enhances the volume shrinkage of hydrogel networks during polymerization, allowing us to modulate internal stresses. Photopolymerization of these polyelectrolyte‐containing solutions through a mask produces mechanically strong hydrogel sheets with large patterned internal stresses. Consequently, these hydrogel sheets attain complex 3D initial shapes at equilibrium, in contrast to the planar initial configuration of 2D actuators. We demonstrate that these 3D actuators can reversibly transform into other 3D shapes (i.e., 3D‐to‐3D shape transformations) in response to external stimuli. Additionally, we develop a predictive model based on the Flory‐Rehner theory to analyze the polyelectrolyte‐mediated shrinking behaviors of hydrogel networks during polymerization, allowing precise modulation of shrinkage and internal stress. This polyelectrolyte‐boosted shrinking mechanism paves a route to the fabrication of high‐performance 3D hydrogel actuators.
Funder
National Natural Science Foundation of China