Characterization of liquid crystal from cellulose nanocrystals

VERÓNICA L. MUCCI; JUAN MANUEL BUFFA; MIRTA I. ARANGUREN

Mar del Plata

Congreso; XVI SIMPOSIO LATINOAMERICANO DE POLÍMEROS Y XIV CONGRESO IBEROAMERICANO DE POLÍMEROS; 2018

INTEMA (UNMdP-CONICET)

Liquid crystals (LCs) are materials that are in liquid statebut have the characteristic long-range order of solid.The order of the system can be characterized byrheological measurements, since the response highlydepends on the forces between the particles.Cellulose nanocrystals (CNCs) are rod-like particles withlengths between 100 and 300 nm and diameters of 5-10nm. Due to this high aspect ratio and the chiral natureof the particles (twisted non-cilyndrical rods), at highconcentrations (over ~2.5 w/w%) they form chiralnematic LCs. The characterization of LC by rheologyrelies on the presence of the so-called signatures: threezones in the 𝜂 (𝛾)̇curve, long time oscillatory transients,a maximum (or a plateau) in the curve of 𝜂 vs. conc., andthe Cox-Merz rule is not obeyed. The presence ofseveral of these characteristics may be evidence of theLC behavior, although, not necessarily all of them mayappear.