Multilayer gels with spatial arrangement of functional nanomaterials

Multilayer gels with different functional properties exhibit various responsive and actuating operations, making them promising for engineering and biomedical applications. However, the fabrication of multilayer gels with sharp functional disparities between layers typically relies on lengthy layer-by-layer syntheses, resulting in weak mechanical and interfacial integrity. Herein, a simple one-step heterogeneous polymerization technique is proposed to fabricate bilayer and trilayer gels with spatially arranged functional nanomaterials. This method offers precise control over the spatial arrangement of functional nanomaterials, leading to a sharp and customizable functional disparity between layers. Further, unlike reported methods, our method offers customization of the entire multilayer structure within a fully continuous, load-bearing polymeric network; therefore, the resulting multilayer gel behaves like a single material without mechanical or interfacial incompatibilities. Notably, it allows the fabrication of multilayer gels from different polymers, crosslinkers, and spatially arranged carbon-based water-dispersible nanomaterials. In this manner, the prepared multilayer gels exhibit flexibility and versatility in terms of their types and functionalities. Various stretchable/flexible devices, including electrical gel wires, supercapacitors, and pressure sensors, are designed using the as-prepared multilayer gels, demonstrating their practical applicability. These devices exploit the functional disparity and strong interfacial integrity between layers of multilayer gels.