Cellulose nanocrystals (CNCs) are a rod-like nanoparticles that can be isolated from native cellulose through various processes. We produce CNCs via acid hydrolysis of cotton-based material, which introduces half-sulphate ester charges to stabilise the CNC suspensions and facilitate a sequential phase transition. The liquid-crystalline nature of CNCs leads to their helicoidal self-assembly and is a well-documented phenomenon. Through evaporation-induced self-assembly (EISA) CNCs start from isotropic suspensions, form tactoids and finally gelate into cholesteric mesophase films. Such films can be used to produce optically active components or processed further. In this study, we explore the parameter space in CNC colloidal suspensions and their interactions with gelation agents to explore the onset of the gelation point via incorporating xanthan gum. Xanthan gum is produced by the fermentation of simple sugars by the bacteria <i>Xanthomas campestris</i>. While the presence of the complex polysaccharide gum brings flexibility to the CNC films, they also demonstrate remarkable colour uniformity and loss of iridescence due to the entrapment of the CNC tactoids into capsule structures to combine a surface texture and scattering of visible light within the co-assembled structure. In this talk, I will explain how in the evaporation stage Xanthan advances the onset of gelation and provides colloidal stability, thus restricting the expected phase separation that arises from the merger of tactoids into large domains. This work sheds new light on the gelation mechanisms in hybrid CNC systems and their interaction with an additive of alike chemistry.

Modified gelation in the self-assembly of CNCs using xanthan gum

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.