Formulation and Characterisation of Reduced Graphene Oxide Dispersions

  • Cian Bartlam

Student thesis: Phd

Abstract

Two-dimensional materials have come to the forefront of material science over the past 10 years. While the potential applications of such materials are vast, viable routes to production are still in their infancy. This thesis focusses on the application of polyaromatic hydrocarbons to graphene and reduced graphene oxide aqueous dispersions, investigating the effect of different aromatic moieties on the dispersion quality of the graphene derivatives. The main aims in this work were to further understand the influence of stabiliser structure on the efficiency of aqueous reduced graphene oxide and liquid exfoliated graphite dispersion while minimising stabiliser excess, determined through final concentration measurements of graphene material and lateral size and monolayer counting of the flakes, the most widely reported metrics for dispersion quality. This has been achieved through the in-situ reduction and stabilisation of graphene oxide under environmentally benign conditions using pyrene, perylene and triphenylene derivatives. Systematic studies showed that stabiliser structure has a large effect on dispersion quality and that through the optimisation of this, the use of sonication can be negated, achieving high lateral flake sizes for reduced graphene oxide at arbitrarily high concentrations and 100% monolayer content when using sulphonated perylenes with large space groups between the polyaromatic core and ionic head. This investigation lead to the development of standard characterisation protocols for these materials, along with characterisation of dispersions produced by exfoliation of graphite by sonication. Further to this, nanoscale characterisation using AFM-IR has been shown to be a new useful characterisation method for two-dimensional materials, able to detect ionic pyrene signatures on monolayer flakes at
Date of Award31 Dec 2019
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorPeter Budd (Supervisor), Stephen Yeates (Supervisor) & Aravind Vijayaraghavan (Supervisor)

Keywords

  • graphene
  • polyaromatic stabilisers
  • reduced graphene oxide
  • AFM-IR
  • dispersions

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