Graphene-Directed Supramolecular Assembly of Multifunctional Polymer Hydrogel Membranes

Polymer-based nanoporous hydrogel membranes hold great potential for a range of applications including molecular filtration/separation, controlled drug release, and as sensors and actuators. However, to be of practical utility, polymer membranes generally need to be fabricated as ultrathin yet mechanically robust, have a large-area yet be defect-free and in some cases, their structure needs the capability to adapt to certain stimuli. These stringent and sometimes self-conflicting requirements make it very challenging to manufacture such bulk nanostructures in a controllable, scalable and cost-effective manner. Here, a versatile approach to the fabrication of multifunctional polymer-based hydrogel membranes is demonstrated by a single step involving filtration of an aqueous dispersion containing chemically converted graphene (CCG) and a polymer. With CCG uniquely serving as a membrane- and pore-forming directing agent and as a physical cross-linker, a range of water soluble polymers can be readily processed into nanoporous hydrogel membranes through supramolecular interactions. With the interconnected CCG network as a robust and porous scaffold, the membrane nanostructure can easily be fine-tuned to suit different applications simply by controlling the chemistry and concentration of the incorporated polymer. This work provides a simple and versatile platform for the design and fabrication of new adaptive supramolecular membranes for a variety of applications.