Conductive hydrogel films produced by freestanding electrophoretic deposition and polymerization at the interface of immiscible liquids

Conductive hydrogels are promising materials for energy and biomedical applications due to their bio-compatibility, high porosity, and outstanding swelling-capability. In this work we present a unique method to fabricate nanomaterial-hydrogel composite films using Electrophoretic Deposition (EPD) at the interface of two immiscible liquids. During interfacial EPD, nanoparticles such as carbon nanotubes (CNTs) electro-migrate to an oil/water interface, where polymer cross-linking is induced to form composite hydrogel films. The key aspect of this method is that polymerization occurs away from a solid substrate while surrounded by both water and oil, allowing for the integration of CNTs into the hydrogel. Properties of the composite hydrogel films are controlled by EPD parameters and polymerization conditions, facilitating the potential for mass production without complex machinery. This fabrication method is cost-effective and scalable for composite hydrogels with tunable electrical, mechanical, and biological properties. Potential applications include fabrication of doped hydrogels for drug delivery and biological sensors.