Improving Redispersibility of Nanocellulose via Interaction with Arginine

Abstract

The high water content of TEMPO-oxidized cellulose nanofibril (TOCNF) suspensions (∼99%) presents a challenge for transportation, leading to higher logistical costs and complicating large-scale production. Drying TOCNFs to a lower water content often results in hornification, which affects their redispersion and reuse. This study examined the interaction between TOCNF and arginine (ARG), an inhibitor of protein aggregation, to improve redispersion after drying. At neutral pH, the ARG addition caused slight charge screening on the TOCNF surface, as observed through zeta potential (ζ-potential) and force spectroscopy (AFM-FS) measurements due to ARG adsorption. Even with an excess of arginine, nanofibril aggregation did not occur, and repulsive interactions among the nanofibrils were maintained (ζ-potential > −25 mV), leading to the formation of a colloidal glass with improved viscosity and elastic modulus at 0.5 wt % of TOCNF. The TOCNF/ARG colloidal glass was redispersed with a high ARG concentration due to steric repulsion and reduced TOCNF adhesion. The redispersed system exhibited the same rheological properties, and the nanofibrils returned to the nanoscale, as observed by cryogenic transmission electron microscopy (cryo-TEM). This study presents a strategy to facilitate the large-scale application of TOCNFs while maintaining their nanostructure and ability to form colloidal glass after redispersion.