Nanoseminar: Assist. Prof. Kazuho Daicho (Department of Biomaterial Sciences, University of Tokyo, JP)

Kazuho Daicho is an Assistant Professor in the Department of Biomaterial Sciences at the University of Tokyo. She obtained her Ph.D. from the University of Tokyo in 2021 under the supervision of Prof. Tsuguyuki Saito, during which she studied the crystallinity of cellulose nanofibers (CNFs). She then spent one year as a postdoctoral researcher in the Fukuma Laboratory at Kanazawa University, where she investigated the hydration structures of polysaccharides. Afterward, she joined the Shiomi Laboratory in the Department of Mechanical Engineering at the University of Tokyo, where she worked on the thermal properties of cellulosic materials before moving to her current position. Her research focuses on the solid-state structural characterization of biomass-derived materials and the relationship between their structures and physical properties.

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Public lectures, seminars and round tables
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English
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Free of charge
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Ylistönrinne
YAA 305

Molecular Mechanism Underlying Crystallinity Changes of Cellulose upon Fibrillation and Reassembly

Assist. Prof. Kazuho Daicho
Department of Biomaterial Sciences, University of Tokyo

Cellulose crystallinity decreases as the cell wall structure of pulp is fibrillated into cellulose nanofibers (CNFs) in water, and partially recovers upon reassembly into bulk structures through dehydration. This phenomenon has been observed not only in TEMPO-oxidized CNFs but also in unmodified CNFs and native cellulose, suggesting that it reflects an intrinsic property of cellulose microfibrils. To investigate the molecular mechanism underlying these crystallinity changes, we performed two-dimensional ¹³C–¹³C DARR solid-state NMR using ¹³C-labeled wood cellulose. The analysis revealed that the surface C4 carbons remained non-crystalline throughout both fibrillation and reassembly, while the inner C4, C5, and C6 carbons underwent a coordinated conformational transition between crystalline and non-crystalline states. These findings demonstrate that the crystallinity changes are governed by the conformational behavior of the interior glucose residues.

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