PREVENTING AGGREGATION AND HORNIFICATION OF OXIDIZED NANOCELLULOSE VIA ARGININE INTERACTION

The high water content of TEMPO-oxidized cellulose nanofibril (TOCNF) suspensions, around 99%, poses significant challenges in transportation, resulting in increased logistical costs and complicating large-scale production efforts. Drying TOCNFs to reduce water content often leads to hornification, compromising their ability to be redispersed and reused effectively. In this work, we investigated the interaction between TOCNF and arginine (ARG), a known protein aggregation inhibitor, to enhance redispersion following drying.

We observed that at neutral pH, the addition of ARG resulted in slight charge screening on the TOCNF surface, as evidenced by zeta potential and force spectroscopy (AFM-FS) measurements indicating ARG adsorption. Even with an excess of arginine, we did not observe nanofibril aggregation, and the repulsive interactions among the nanofibrils were preserved (ζ-potential > −25 mV), leading to the formation of colloidal glass with improved viscosity and elastic modulus. The TOCNF/ARG colloidal system could be effectively redispersed at high ARG concentrations, and we attributed this to steric repulsion and decreased TOCNF adhesion. Cryogenic transmission electron microscopy (cryo-TEM) demonstrated that the morphology of redispersed nanofibrils after drying remained consistent with their pre-dried state, thereby confirming the re-establishment of the colloidal glass network.

This study presents a potential solution for using TOCNF after drying, ensuring the preservation of its nanostructure and colloidal properties upon redispersion.

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