In this work, linear polystyrene-poly(2-vinylpyridine) (PS-b-P2VP) and heteroarm star PS_22P2VP_22 ionizable block copolymers were used as dispersing agents for the liquid-phase exfoliation of pristine graphene. Various strategies such as direct exfoliation, film hydration and phase transfer have been employed and compared. The best strategy involved a two-step process, namely, pre-exfoliation of graphite in polymer/CHCl3 solutions followed by phase transfer to acidified water. High concentrations of stable aqueous suspensions of graphene flakes, highly enriched in monolayer structures, were then obtained by using the star-shaped copolymers as stabilizers. The as-prepared graphene/copolymer hybrids were used as a filler material in order to prepare functional polymer composites for mechanical reinforcement. Such copolymer-modified graphene sheets have proven to be efficient reinforcing agents of PVA, as a significant increase of storage modulus (145% higher than that of neat PVA) was achieved even at a low graphene weight fraction of 0.1 wt%.
@article{arxiv.1801.07069,
title = {Colloidal stabilization of graphene sheets by ionizable amphiphilic block copolymers in various media},
author = {Maria-Teodora Popescu and Dimitrios Tasis and Konstantinia D. Papadimitriou and Sandra Gkermpoura and Costas Galiotisac and Constantinos Tsitsilianis},
journal= {arXiv preprint arXiv:1801.07069},
year = {2018}
}