Fragmented liquid crystals of graphene oxide

Repulsive colloids can form liquid crystals (LCs) that combine fluidity and structural order. Screening repulsion leads to abrupt collapse of LC, losing fluidity either by gelation or frustrating structural order by coagulation. However, the evolution of liquid crystallinity before the transition from overall repulsion to attraction remains unclear. Here we find an intermediate LC state of graphene oxide (GO), named as fragmentated LC (FLC). FLC features fragmented domains down to single entity size but keeps good fluidity contrary to gel and coagulation. In FLC, the balanced interaction keeps single-layer dispersed state of GO and triggers transient networks. GO FLCs surprisingly serve as a peculiar processing state towards amorphous but compact structures with both high strength and toughness, beyond brittle crystalline structures assembled from ordinary nematic LCs. Our findings enable precisely modulating LC directors down to the molecular size limit and provide a new design method for exotic amorphous materials.