Stimuli induced cellulose nanomaterials alignment and its emerging applications: A review

The developments of cellulose nanomaterials (CNMs) require in-depth understandings of the process-structure-property-performance relationship. Limited control over CNMs orientations in advanced materials has been a major bottleneck in the exploration of the full potential of these fascinating CNMs. Alignment promotes a realizable reduction of defect size in neat CNMs films or nanocomposites. Here, we have reviewed the recent advances in CNMs alignments. This review begins with a short introduction to the most relevant properties of CNMs. Also, we have described the techniques for characterizing the alignments. Then stimuli induced CNMs alignments in neat matrices and hybrid composites are extensively explored with a focus on the alignment dynamics. Particular attention is paid to the synergistic effects of multiple stimuli. The aligned CNMs provide a versatile platform to tailor structures and properties for desired applications. Finally, the challenges and opportunities in stimuli driven CNMs alignments are discussed.