Ordering in GO-CNT Hybrid Nanostructures via Polyelectrolyte Assisted Self-Assembly

Self-assembly of nanoparticles offers creative pathways to organize individual components into a complex nanostructure with precise spatial arrangements. Anisotropic nanoparticles such as 2D-graphene/graphene oxide, and 1D-carbon nanotubes can be self-assembled, with the help of polyelectrolytes, in the formation of hybrid structures with enhanced electrical, thermal, and mechanical properties [1, 2]. The incorporation of polyelectrolytes facilitates the assembly process by leveraging electrostatic interactions, in the formation of spontaneous and well-defined architectures. We utilise Coarse-grained molecular dynamics simulations to study the pathways and governing parameters in self-assembled GO-CNT hybrid nanostructures. GO and CNTs are modified with Cationic (PEL(+)) and Anionic polyelectrolyte (PEL(-)) respectively, and mixed with different relative concentrations to form assemblies. These assemblies can be fine-tuned by adjusting parameters related to electrostatic interaction between particles, such as (a) charge density on the surface of GO sheets, and (b) strength of polyelectrolytes. We aim to optimise the adsorption of CNTs on GO sheets and maximise the ordering of CNTs in uniform arrangement. It was found that an increase in the concentration of anionic polyelectrolyte (PEL(-)) adsorbed CNT, was found to increase the number of CNT adsorbed at a given charge density of GO. Also, the mobility of PEL(+) on the GO surface by grafting the PDDA affected the arrangement of CNTs, showing the need for mobile polyelectrolytes in an ordered arrangement. This study will lead us to formulate highly ordered GO-CNT hybrids with astounding control over the ordering of CNTs between GO sheets, which could improve the functioning of hybrid nanostructure in various applications such as membrane, catalysis, and supercapacitors.<br/><br/>References:<br/>1. Vinayan, B.P., et al., Synthesis of graphene-multiwalled carbon nanotubes hybrid nanostructure by strengthened electrostatic interaction and its lithium ion battery application. Journal of Materials Chemistry, 2012. 22(19): p. 9949-9956.<br/>2. Goh, K., et al., All-Carbon Nanoarchitectures as High-Performance Separation Membranes with Superior Stability. Advanced Functional Materials, 2015. 25(47): p. 7348-7359.