Chemically Coupled Interfacial Adhesion in Multimaterial Printing of Hydrogels and Elastomers

Abstract

Functional devices that use hydrogels as ionic conductors and elastomers as dielectrics have the advantage of being soft, stretchable, transparent, and biocompatible, making them ideal for biomedical applications. These devices are typically fabricated by manual assembly. Techniques for the manufacturing of soft materials have generally not looked at integrating multiple dissimilar materials. Silane coupling agents have recently shown promise for creating strong bonds between hydrogels and elastomers but have yet to be used in the extrusion printing of complex devices that integrate both hydrogels and elastomers. Here, we demonstrate the viability of silane coupling agents in a system with the rheology and functional composition necessary for three-dimensional (3D) extrusion printing of hydrogel–elastomer materials, specifically polyacrylamide (PAAm) hydrogel and poly­(dimethylsiloxane) (PDMS) hydrophobic elastomer. By introducing a charge-neutral surfactant in the PDMS and adjusting silane concentrations in the PAAm, cast material samples demonstrate strong adhesion. We were also able to achieve an interfacial toughness of up to Γ = 193 ± 6.3 J/m2 for a fully extrusion printed PAAm hydrogel-on-PDMS bilayer. This result demonstrates that an integration strategy based on silane coupling agents makes it possible for extrusion printing of a wide variety of hydrogel and silicone elastomers.

Engineering Hydrogel Adhesion for Biomedical Applications via Chemical Design of the Junction

“…143 Further, the attachment kinetics were tuned by changing temperature, varying pH, or adding surfactants. This general scheme has also been applied for attaching magnetic polymers 144 and for gluing hydrogels and elastomers 145 as well as for other bonding approaches such as multimaterial printing of hydrogels and elastomers 146 and hydrogel coatings. 147 5.1.4.…”

Constructing Flexible All‐Solid‐State Supercapacitors from 3D Nanosheets Active Bricks via 3D Manufacturing Technology: A Perspective Review

“…Constructing flexible all-solid-state supercapacitors from 3D nanosheets active bricks (powder materials) via 3D printing technology is highly feasible, based on previous successes in 3D MoS 2 nanosheets [34] and 3D Ti 3 C 2 T x nanosheets. [35] Nevertheless, compared with the colloidal 2D nanosheets, the preparation of printable ink for 3D printing may face more difficult problems for the 3D nanosheets powders (more nanofiber additives [114,115] or coupling agents [105,141] may be required), probably due to their large self-assembly volume and/or lack of hydrophilicity. Specifically, the ink material for 3D printing needs to have the rheological behavior of shear thinning, so as to flow continuously and stably under the action of high shear rate.…”

Mechanomaterials: A Rational Deployment of Forces and Geometries in Programming Functional Materials

“…Topological entanglement has been developed at the elastomerhydrogel interface, [48,179,180] hydrogel-hydrogel interface, [181,182] and hydrogel-tissue interface, [47] thereby enabling strong adhesion of the two. There are also methods using covalent bonding directly between two polymeric networks, [179,183,184] which will not be discussed here.…”