Recent Progress in Cellulose Nanocrystal Alignment and Its Applications

Cellulose nanocrystal (CNC) research has addressed increased attention in the bioprocessing community, especially the utility of these materials in different fields, including biomedical and materials applications. In this review, the different preparation methods and properties of CNC materials will be initially briefly discussed. The latter focuses special attention on the alignment of CNCs and its applications. Different methods to induce CNC alignment, including self-assembly, shear-based alignment, magnetic and electric field alignment, spin-coating, dip-coating, etc., are reviewed in detail, followed by the different characterization techniques to quantify the alignments of CNCs. The current and potential applications of aligned CNCs, such as fillers to enhance the mechanical and thermal properties of biocomposites, photonic materials to deal with structural colors and enhancement in optical properties of iridescent films, and reduced wettability for high-resolution printing, are further discussed to provide more insights into this promising research direction. We hope that this review will shine light on CNC alignment and also open the door to different types of applications.