Effect of Fibril Length on the Ice Recrystallization Inhibition Activity of Nanocelluloses

Ice recrystallization inhibition (IRI) activity has been recently discovered on nanocelluloses, which enables potential applications in several fields. This study focused on the effect of fibril length on the IRI activity of nanocelluloses. The 2, 2, 6, 6-tetramethylpiperidine-1-oxyl oxidized cellulose nanofibrils (TEMPO-CNFs) with similar surface charge densities (SCDs) and fibril widths, but with different fibril lengths were prepared by sonication treatment. The IRI activity of nanocelluloses was enhanced in TEMPO-CNFs receiving sonication less than 30 min because of the reduction of fibril aggregation. Further increase of sonication time to 60 and 120 min led to a decreased IRI activity due to the reduction of fibril lengths. Our results indicate longer nanocelluloses are more IRI active. The IRI activity was not correlated with the viscosity or gelling properties of nanocellulose dispersions. Research findings are useful in producing nanocelluloses with enhanced IRI activity and in understanding the underlying IRI mechanism.