Synthesis of graphene-based amphiphilic Janus nanosheets via manipulation of hydrogen bonding

The economical synthesis of amphiphilic Janus nanosheets in large amounts for practical applications is a grand challenge. This work reports a facile and scalable method to prepare graphene-based amphiphilic Janus nanosheets with much higher efficiency than the previously-reported wax template masking method. Graphene oxide (GO) was immobilized by hydrogen bonding on the surfaces of starch microspheres, confirmed by both experiments and Molecular Dynamics simulations. After selective functionalization of the exposed surface with alkylamine, amphiphilic Janus nanosheets (AJN) were obtained by releasing the nanosheets from the starch microspheres via breaking the hydrogen bonding. The interfacial behavior of AJN shows its amphiphilicity and the asymmetrical surface wettability indicated from the difference of contact angles, further demonstrated its Janus nature. In addition, avoiding of dissolving the template materials in comparison with wax masking method was also benefit for environment and recycling.