Restructuring of Hydrogel Polymer Networks via Ion Storming.

Hydrogel is a 3D network gel with high hydrophilicity, and its mechanical properties are weakened by the disordered polymer network. Although traditional techniques such as directional freezing and salting-out improve the mechanical properties of the hydrogel, the biomedical and chemical engineering applications are limited by the complex processing procedures. In view of this situation, an urgent demand for the non-intrusive in situ hydrogel processing technique is required, and the disordered polymer network resembles a tangled yarn that can be unraveled through the external electric field. It is of interest to elucidate whether there are countless ions at the atomic-scale that can instantly align the disordered polymer networks in the hydrogel. In this study, it is first demonstrated that these ions can move in the hydrogels under the action of the electric field. The rapid ion vibrations break the hydrogen bonds to restructure the networks under the action of the high-frequency electric field, and the soft hydrogel is formed; while that generates the coordination under the action of the low-frequency field, and the tough hydrogel is obtained. This technique integrates the structure and material in the hydrogels, which enhances the mechanical properties of the 3D-printed hydrogel components.