Reinforcement of GO composites using rigid and flexible crosslinkers

Kaur, Purneema; Bowen, Leon; Hutchings, Lian R.; Chaudhry, Mujeeb U.; Pugh, Thomas; Thompson, Richard L.

Abstract

Crosslinkers are important for graphene oxide (GO) plates in filtration applications because they help to define and maintain the integrity of the nanoscale structure. GO platelets were dispersed in aqueous solution and crosslinked using a simple “one-pot” process in which multi-amine functional molecules could react with carboxylic acid or epoxy groups of the GO surfaces. Strain-sweep oscillatory rheology enabled a detailed analysis of the reinforcing behaviour of crosslinkers on GO. Flow stress analysis of three different types of reinforced GO composites shows significant increases in the elastic modulus of the GO composites, compared to non-crosslinked GO. Crosslinkers were octaammonium polyhedral oligomeric silsesquioxane, (OA-POSS), a rigid cage, low Mw (0.8 kg/mol) or high Mw (25 kg/mol) chain branched polyethyleneimine, PEI (flexible). Crosslinking with either of the PEI polymers increases the yield stress of GO composites up to 20 times more than the rigid OA-POSS crosslinker, and nearly 170 times more than the non-crosslinked GO. The ‘one pot’ synthetic route employed in this work shows that maximum levels of reinforcement are relatively insensitive to crosslinker concentration. The yield stress of all three types of composites increases sharply as a function of crosslinker concentration, reaching a broad plateau, before decreasing slightly. The decrease in reinforcement at high concentrations may be attributed to the saturation of available sites on GO nanosheets inhibiting crosslinking. Composites crosslinked in-situ included a significant fraction of water which was excluded under compression. Crosslinked GO samples under compression showed an increase in the elastic modulus consistent with an increase in the effective concentration of composite. GO-coated membranes showed high rejection (up to ∼90 %) of Rhodamine WT, and the resilience of these membranes was visibly improved with very low crosslinker loadings, 0.2 % w/w with respect to the mass of GO.

Citation

Kaur, P., Bowen, L., Hutchings, L. R., Chaudhry, M. U., Pugh, T., & Thompson, R. L. (2025). Reinforcement of GO composites using rigid and flexible crosslinkers. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 709, Article 136156. https://doi.org/10.1016/j.colsurfa.2025.136156

• Journal Article Type: Article
• Acceptance Date: Jan 7, 2025
• Online Publication Date: Jan 15, 2025
• Publication Date: 2025-03
• Deposit Date: Jan 31, 2025
• Publicly Available Date: Jan 31, 2025
• Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects
• Print ISSN: 0927-7757
• Electronic ISSN: 1873-4359
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 709
• Article Number: 136156
• DOI: https://doi.org/10.1016/j.colsurfa.2025.136156
• Public URL: https://durham-repository.worktribe.com/output/3342548
• Additional Information: This article is maintained by: Elsevier; Article Title: Reinforcement of GO composites using rigid and flexible crosslinkers; Journal Title: Colloids and Surfaces A: Physicochemical and Engineering Aspects; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.colsurfa.2025.136156; Content Type: article; Copyright: © 2025 Published by Elsevier B.V.