Graphene quantum dots (GQDs) are a subset of the nanocarbon material family, which promise a wide spectrum of applications. Herein, we describe amphiphilic graphene quantum dots with zwitterionic features (ZGQDs), which are able to stabilize the oil/water interface. ZGQDs were fabricated by modifying GQDs with tertiary amine groups and alkyl groups. Moreover, the blocking and unblocking behavior of ZGQDs at the oil/water interface could be tuned by adjusting pH values in the aqueous phase. It would provide a flexible and adjustable method to manipulate interfacial properties of ZGQDs, which enabled a switchable molecular diffusion through a fluid-fluid interface. ZGQDs have shown well-controlled interfacial behavior under different pH conditions, indicating great potential for applications in controlled molecular diffusion based on nanoparticles demonstrated in this work.
Keywords: Pickering emulsifier; controlled-release; graphene quantum dots; pH-responsive; zwitterionic.