Tough Bonding, On‐Demand Debonding, and Facile Rebonding between Hydrogels and Diverse Metal Surfaces

Abstract

Hybrid systems of hydrogels and metals with tough bonding may find widespread applications. Here, a simple and universal method to obtain strong adhesion between hydrogels and diverse metal surfaces, such as titanium, steel, nickel, tantalum, argentum, and aluminum, with adhesion energy up to >1000 J m−2 is reported. To achieve such, the metal surfaces are instantly modified with a linker molecule via soaking, dip‐coating, or drop‐casting. The designed linker molecule has a carboxylic acid group to bind with a metal surface, and a methacrylic group to crosslink with a hydrogel, thus bridging the interface between them. In addition, by introducing a stimulus‐responsive disulfide bond into the linker molecule, the on‐demand debonding between toughly bonded hydrogel and metal surface, which is enabled by reductive cleavage of the disulfide chemical linkage, is also demonstrated. More interestingly, after the reductive debonding, the resulting metal surface with free thiol groups can be easily rebonded with a second hydrogel without any further surface modification. The strategy may provide unique opportunities in designing hybrid devices that are suitable for complex and dynamic environments.

Supramolecular adhesive materials from small‐molecule self‐assembly

“…89,90 Consequently, the ondemand (de)bonding of hydrogels and solid substrates may construct new functional synergistic materials for usage in dynamic and complex conditions. Li et al 91 created a simple approach for instant on-demand (de) bonding of hydrogel to various metal surfaces with arbitrary shapes. They designed a 14-1 molecule, where 14-1 contains a carboxylic acid group binding with the metallic surfaces and a methacrylic group chemically connected with the polymeric hydrogel network.…”

Hierarchically Molecular Imprinted Porous Particles for Biomimetic Kidney Cleaning

“…Removal of these biomolecules from blood is vital for human health. [1][2][3] For this purpose, a series of in vitro blood purification techniques have been developed, including physical adsorption, [4][5][6][7] hemodialysis, [8,9] hemofiltration, [10] plasma exchange, [11] etc. These methods show certain removal capacities while also have limitations, in terms of non-specific adsorption and poor biocompatibility of the dialysis/filtration materials used.…”

Bioinspired tough gel sheath for robust and versatile surface functionalization

“…For surface functionalization of surgical sutures, hydrogel technologies are promising in light of recent developments of tough hydrogel adhesion on various materials such as tissues ( 3 ), hydrogels ( 26 ), metals ( 27 ), and elastomers ( 28 ). These established strategies exploit preformed hydrogel patches to be applied on flat surfaces and thus are not compatible with fiber-based devices as sutures.…”