Production of a Metallic Single Gyroid with a Tunable Sub-10-nm Unit Cell Size via Lipid-Cubic-Phase Templating: Chiral Nanomaterials for Catalytic and Optical Applications

We present the production of a metallic single-gyroid nanomaterial by using lipid-cubic-phase templating. Single-gyroid materials are chiral nanowire networks whose chirality potentially gives rise to optical metamaterial behavior, leading to considerable recent scientific interest. Until now, single-gyroid materials have been fabricated by using block copolymer templates, producing unit cell sizes down to 20 nm. Here, we present the use of a lipid-cubic-phase template with which we can produce single-gyroid structures with unit cell sizes of less than half that of the smallest reported previously. Single-gyroid platinum materials with controllable unit cell sizes between 8.4 and 9.5 ± 0.3 nm can be produced by using different lipid proportions in the template. Furthermore, the template self-assembles spontaneously; metal deposition is achieved in an aqueous solution through galvanic displacement on a stainless steel substrate at room temperature, and the template dissolves in ethanol after deposition. The process is therefore straightforward and synthetically attractive, avoiding the complex multistep routes and elevated temperatures associated with block copolymer templating routes to single-gyroid nanomaterials.