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Structure of cellulose microfibrils in mature cotton fibres

Martínez-Sanz, Marta, Pettolino, Filomena, Flanagan, Bernadine, Gidley, Michael J., Gilbert, Elliot P.
Carbohydrate polymers 2017 v.175 pp. 450-463
Gossypium hirsutum, cell walls, cellulose microfibrils, crystal structure, lint cotton, models, solvents, spectroscopy
The structure of cellulose microfibrils in mature cotton fibres from three varieties – Gossypium hirsutum, G. barbadense and G. arboreum – has been investigated by a multi-technique approach combining small angle scattering techniques with spectroscopy and diffraction. Cellulose microfibrils present a Iβ-rich crystalline structure with limited surface disorder. Small angle scattering (SAXS and SANS) data have been successfully fitted using a core-shell model and the results obtained indicate that the cellulose microfibrils, formed by the association of 2–3 elementary fibrils, are composed of a ca. 2nm impermeable crystalline core, surrounded by a partially hydrated paracrystalline shell, with overall cross-sections of ca. 3.6–4.7nm. Different low levels of cell wall matrix components have a strong impact on the microfibril architecture and enable moisture penetration upon hydration. Furthermore, the higher amounts of non-cellulosic components in G. barbadense result in a less dense packing of cellulose microfibrils and increased solvent accessibility.