Cellulose and Chitin Twisted Structures: From Nature to Applications

Abstract

Twisted structures are ubiquitous in plants and animals. Cellulose and chitin are natural polymers that form the structural skeleton of various twisted systems observed across different length scales, ranging from the molecular to the nano, micro, and macro scale. In addition, cellulose and chitin helicoidal structures are found to be responsible for structural coloration, enhanced mechanical properties, and motion. This review first addresses cellulose and chitin‐based chiral molecular systems and nanoscale helicoidal arrangements. Attention is given to cellulose nanocrystals, water interactions, out‐of‐equilibrium structural colorful structures formed by cellulose derivatives, and chitin's optical and mechanical properties. The discussion progresses to the micro and millimeter scales, where specific examples are presented to showcase specialized helical cellulose‐based organizations. The chosen examples illustrate the formation of different helicities, adaptative shapes, and movements at varying length scales, such as in vascular leaf petioles at the micro‐scale and millimeter‐scale in tendrils and awns of Erodium fruits. So far, the results indicate that significant work should be done on out‐of‐equilibrium systems. In addition, much must be learned from nature to produce novel twisted functional materials. This work aims to provide a comprehensive overview of the state‐of‐the‐art study of twisted cellulose and chitin‐based structures and their potential applications.

Structural, Optical, and Mechanical Insights into Cellulose Nanocrystal Chiral Nematic Film Engineering by Two Assembly Techniques

“…Chiral nematic structures are known for their exceptional mechanical robustness, possessing multiple toughening mechanisms that enhance their mechanical properties. Chiral nematic structures are complex three-dimensional structures arranged in torsional layers . This structure is maintained by noncovalent bonding interactions, enabling the material to absorb external forces and dissipate energy efficiently through intermolecular motions and rearrangements .…”

“…Chiral nematic structures are complex three- dimensional structures arranged in torsional layers. 64 This structure is maintained by noncovalent bonding interactions, enabling the material to absorb external forces and dissipate energy efficiently through intermolecular motions and rearrangements. 65 At the same time, the angular differences between the layers create barriers to crack extension and increase toughness by deflecting crack paths.…”

Water-Driven Sol–Gel Transition in Native Cellulose/1-Ethyl-3-methylimidazolium Acetate Solutions

“…This goes beyond the linear dependence of the modulus on the cross-link concentration, suggesting a more complex network configuration compared to that schematized in Figure B,C. Indeed, various authors − report that cellulose chains in solution, in the presence of water, form heterogeneous bundles or ordered mesophases, depending on the grade of cellulose used. Also, Tharmann et al reported that the modulus of cross-linked actin gels varies with the power of 3.5 of the cross-linker concentration, and this was ascribed to the formation of actin chain bundles.…”