Cellulose nanocrystals to modulate the self-assembly of graphene oxide in suspension. (April 2022)

• Record Type: Journal Article
• Authors: Singh Raghuwanshi, Vikram; Varanasi, Swambabu; Batchelor, Warren; Garnier, Gil
• Is Part Of: Materials & design. Volume 216(2022)
• Publication Date: 2022-04
• Subjects: Cellulose nanocrystals -- Graphene oxide -- Self-assembly -- Isotropic -- Nematic -- Small angle X-ray scattering; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.110572
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: The self-assembly of graphene oxide (GO) sheets and cellulose nanocrystals rods (CNC) in CNC/GO composite suspension is studied by SAXS. Mixing isotropic and nematic phases of CNC with GO at different CNC/GO ratios shows transition from isotropic to biphasic and a nematic state. At a higher CNC/GO ratio, the CNC rods force the GO sheets to align in the direction of the CNC nematic assembly. This novel self-assembly mechanism of CNC-GO composites can prevent graphene aggregation on reduction for specific application. Abstract: Controlling the self-assembly(SA) of cellulose nanocrystals(CNC) and graphene-oxide(GO) sheets at nanoscale is crucial for exploiting properties of both CNC and GO. The SA mechanism of GO, CNC and CNC/GO in suspension is evaluated at different concentrations and mixing ratios. SAXS determine the interparticle distance, interaction and distribution of CNC and GO to resolve the self-assembling mechanism. At lower concentrations, the GO sheets are distributed randomly and separated by a large inter-sheet distance of 83 nm with poor inter-sheet interaction. As increases the GO concentration, the inter-sheet repulsion results in a nematic arrangement with the inter-sheet distance decreasing from 83 to 52 nm. Mixing isotropic and nematic phase of CNC with GO at different CNC/GO ratio from 2 to 50 shows transitions from isotropic, to biphasic and nematic state. In isotropic state, at low CNC/GO ratio, the GO sheets are randomly distributed between the CNC rods which increases the CNC inter-rod distance from 22 to 51 nm. However, at higher CNC/GO ratios, steric repulsion from the large amount of CNC forces the GO sheets to align following the direction of CNC nematic assembly. Understanding SA mechanisms of nanostructures in CNC-GO hybrid will enable to engineer applications for sensor, electronics and diagnostics.