Finalist EPFL doctorate Award 2015 – Stephen Schrettl

Carbon nanomaterials offer intriguing perspectives for technological applications, especially, if prepared in a way that enables control of their morphology and chemical functionalization. In this context, we have developed a novel approach for the low-temperature, wet-chemical preparation of two-dimensional carbon nanostructures (nanosheets).

The foundation of this approach is the synthesis of suitable precursor molecules. We devised a versatile synthetic strategy to prepare hexayne carboxylates on the multi-gram scale. The latter represent reactive, carbon-rich siblings of typical fatty acid ester amphiphiles and are designed to self-assemble at the air-water interface. The investigation of the film formation of these amphiphiles confirmed the presence of a well-defined monolayer with a densely packed array of the hexayne moieties. Complete carbonization of the films at the air-water interface was accomplished by cross-linking of the hexayne layer through UV irradiation at room temperature, furnishing a carbon material otherwise only obtained at temperatures beyond 800°C.

In this way, we prepared mechanically stable and rigid, functionalized carbon films with a molecularly defined thickness below 2 nm and lateral dimensions on the order of centimeters. The benign conditions of preparation opened new avenues for applications of the obtained carbon nanosheets as protective coatings, transparent and conformal electrodes, or membrane materials.