Synchronous enhancement and stabilization of graphene oxide liquid crystals: Inductive effect of sodium alginates in different concentration zones

Abstract

A facile way to simultaneously induce the formation and enhance the stability of graphene oxide liquid crystals (GO LCs) is reported. Sodium alginate (SA) with both inductive effect and stabilization effect was added into GO suspensions to prepare LCs at low concentration that could survive harsh conditions. Most importantly, different concentration zones of SA brought significantly different LCs degree and stability, which possessed distinct charge properties, rheological behaviors and chain morphology. Adding 0.5% SA located in entangled semi-dilute regime could induce the isotropic-nematic transition of GO at low concentration (<0.035%) and showed excellent liquid crystalline behavior due to the enhanced electrostatic repulsion of GO/SA colloids, while 1% SA located in concentrated solution regime brought better tolerance to NaCl, MgCl2, FeCl3, serum and pH of 1–13 due to the stronger bounding effect of entanglement network structure to countra-ions. This work develops a simple and eco-friendly method to prepare stable GO LCs at low GO concentration with application potentials especially in biomedical field, and the relationship between the concentration zones of SA and LCs behavior offers theoretical guidance for the self-assembly of GO macrostructures and design and efficient processing of its composites.