Chiral nematic cellulose nanocrystal composites: An organized review

Abstract

Cellulose nanocrystals (CNCs) are commercially available materials derived from cellulose, the most abundant biopolymer on our planet. Due largely to their high strength, high surface area‐to‐volume ratio, tailorable surface chemistry, and the abundance of biomass feedstocks with which to produce them, CNCs have attracted significant interest in applications spanning the paints and coatings, composites, packaging, and biomedical sectors. However, and perhaps most interestingly, CNCs will self‐assemble (or, as I've teased in the title, organize) to form highly ordered chiral nematic liquid crystal phases when concentrated in suspension. Upon complete solvent evaporation, this chiral nematic order is ‘locked’, yielding films with structural colour—colour arising not due to chemical pigments, but rather due to the physical structure of a material itself. In the pursuit of novel multi‐functional materials, research interest has shifted recently towards the incorporation of functional additives to form composite chiral nematic films. Along with introducing the basics of liquid crystals and self‐assembly, this review discusses the main approaches used in order to form CNC‐based composite films: co‐assembly, templating, and post‐processing, and highlights exceptional examples in each case. Finally, I give my uniquely Canadian perspective on the current status, future prospects, and major challenges associated with the development of CNC‐based chiral nematic composite materials.

Screening of Miscanthus Genotypes for Sustainable Production of Microcrystalline Cellulose and Cellulose Nanocrystals

“…Now-a-days, cellulose nanocrystals (CNCs) extracted using MCC have gained significant attention from researchers and scientists in the materials science community due to their exceptional crystallinity, remarkable surface properties, and impressive tensile strength (particularly reaching up to 150 and 10 Gpa, as reported) [6]. In addition to these properties, their exceptional chemical stability, biocompatibility, renewability, non-toxicity, abundant availability from economic sources, low gas permeability, and functional surfaces are highly valued for a wider range of applications including polymer nanocomposites, packaging materials, lithium-ion batteries, drug delivery systems, tissue engineering scaffolds, and protective coatings [7]. Generally, acid hydrolysis is the most popular method for preparing CNCs because of its low cost, short reaction time, and high yield [8].…”

“…Ni-filtered Cu Ka radiation (k = 0.15406 nm) was generated at a voltage of 40 kV and a current of 30 mA and scanned at a speed of 5 • /min from 10 • to 35 • . The CrI was estimated using the intensity of the 200 peak (I 200 , 2θ = 22.5 • ) and the intensity at the minimum between the 200 and 110 peaks (I am , h = 18.5 • ) as follows (7):…”

“…All experiments were performed using Ubbelohde viscosity meter and copper(II) ethylenediamine complex (0.5 M solution in H 2 O). Since the viscosity of the copper ammonia solution was easily affected by temperature, the value of the measured polymerization degree generally decreased with the increased in temperature to ensure the reaction temperature was strictly controlled at 25 • C. The intrinsic viscosity was calculated through interpolation using the USP table (USP, 2002) that lists the predetermined values of the product of intrinsic viscosity and concentration, ([ Agronomy 2024, 14, x FOR PEER REVIEW the intensity of the 200 peak (I200, 2θ = 22.5°) and the intensity at the minimum the 200 and 110 peaks (Iam, h = 18.5°) as follows (7):…”

“…T the value of R 2 was close to 1, the lower MSE, RMSE, MAE, and MAPE were and t accurate the forecasting of the model was. The calculation formulas of R 2 , MSE MAE, and MAPE are shown as follows: the intensity of the 200 peak (I200, 2θ = 22.5°) and the intensity at the minimum between the 200 and 110 peaks (Iam, h = 18.5°) as follows (7):…”

“…), mean squared error (MSE), root mean squared error (RMSE), mean lute error (MAE), and mean absolute percentage error (MAPE) in the test sets. The the value of the intensity of the 200 peak (I200, 2θ = 22.5°) and the intensity at the minimum between the 200 and 110 peaks (Iam, h = 18.5°) as follows (7):…”