Self-limiting Selective Phase Separation of Graphene Oxide and Polymer Composites Solution

Abstract

Homogeneous mixtures undergo phase separation to generate rich heterogeneous structures and enable complex physiological activity and delicate design of artificial materials. Beyond in free space, the strong coupling between migrating components and spatial confinement determines the essential spatial compartment of phase separation and waits to be continuously explored. Here, we report a selective phase separation (SPS) behavior of polymers under the mobile two-dimensional (2D) confinement by graphene oxide (GO) sheets. The selection of poor solvent triggers the occurrence of SPS in homogeneous solution of GO and polymers. We reveal that the self-limiting spatial confinement of GO sheets prefers the migration of polymers to form independent and continuous phase in 2D gallery. We conclude the quantitative rule of size and continuity of polymeric phases in correlation with solvent properties and solute constitutes. The found SPS allows the facile generation of heterogenous nanostructures in GO/polymer composites. We initiate a SPS wet-spinning to fabricate radial heterogenous fibrous graphene composite fibers with ultrahigh breakage elongation and superior flexibility. The found SPS can inspire more exotic phase separation behaviors under mobile 2D confinement and offers a facile method to delicate design heterogeneous nanostructure of 2D materials.