Electrochemical Bonding of Hydrogels at Rigid Surfaces

Abstract

Flexible hydrogels can be chemically/physically bonded on soft surfaces. However, there is a lack of a facile method to build strong interfacial adhesion between hydrogel and various rigid surfaces. Herein, an electrochemical bonding protocol, which improves the interfacial adhesion energy of hydrogel from initial 8 to 3480 J m−2, ≈435 times enhancement at rigid glass surface, superior to the most of traditional methods, is proposed. A series of electrochemical bonding models to analyze the bonding mechanism, is demonstrated. The results indicate that the electrode reactions generate Fe3+ ions at the anode and OH− ions at the cathode, which migrate and react to form nanoparticles of Fe(OH)3. These nanoparticles form hump‐like physical structures at the interface and work as mechanical‐bonding sites, enabling the strong interfacial adhesion. Upon applying acidic solution to decompose the nanoparticles, the strong adhesion can be weakened to easily remove hydrogel from the bonded surface. The electrochemically‐bonded hydrogel can maintain its adhesion in water, which enables the electrochemical bonding of hydrogels for repairing various damaged surfaces such as plastic water tubes/bags, indicating promising potential for adhesive engineering applications.

Electrically driven hydrogel actuators: working principle, material design and applications

“…143 The liquid-solid conversion process inherent in these methods facilitates the formation of tailored hydrogel shapes. 144,145 Additionally, the utilization of photolithography and 3D printing exploits the light-curing properties of hydrogels, enabling the fabrication of hydrogels with intricate micro-and nanostructures. 146,147 The shape and dimensions of hydrogels play a pivotal role in enabling specific actuation modes in soft actuators, such as bending, crawling, locomotion, or other specific tasks.…”

Janus hydrogels: merging boundaries in tissue engineering for enhanced biomaterials and regenerative therapies

“…cular or particle migration. [83][84][85][86] Therefore, investigating the surface and interfacial interactions of Janus hydrogels is crucial for a deeper understanding of their properties and applications, particularly in liquid-phase immobilization and multiphase reactions (Fig. 7).…”

Reversibly Sticking Metals and Graphite to Hydrogels and Tissues

“…When the field is turned off, the materials quickly lose this electrostatic adhesion; thus, this phenomenon allows metallic grippers in a robot to pick up objects and then release them. , Note that this electrostatic effect cannot lead to permanent adhesion in the absence of the field. To our knowledge, the only example of enduring hard–soft adhesion induced by an electric field was the recent study of Qiu et al The authors contacted a hydrogel with glass as well as two iron electrodes and applied a DC field of ∼6 V for several hours. The glass (but not the electrodes) adhered to the gel, and this was attributed to the formation of iron­(III) hydroxide nanoparticles at the gel-glass interface.…”