Cellulose nascent crystals or cellulose microfibrils, extracted from biomass through TEMPO-mediated oxidation, are low cost, biocompatible and high performance materials that have found wide applications in various fields, including water purification, polymer nanocomposites, biosensors, tissue engineering, and etc. However, some fundamental aspects of the structure characterization of these cellulose nascent crystals are still ambiguous. This study demonstrated the use of synchrotron small-angle X-ray scattering (SAXS) technique to characterize the structure of cellulose nanofibers (aggregates) and disperse microfibrils from various sources (e.g. wood, bamboo, cotton, jute, etc.) in aqueous suspension. It is revealed that typical cellulose nanofibers extracted from dried wood pulp are of ribbon shape with length of about 1 mm and cross-section sizes ranging from 3 nm ´ 8 nm to 9 nm ´ 20 nm, depending on the source. Cellulose nascent crystals extracted from never-dried dilignified Spruce wood are in the form of ‘nanostrips’ with width and thickness of around 4 nm and 0.5 nm, respectively. The thickness determination indicates that these nanostrips are comprised of only one layer of cellulose molecules. The molecular arrangement in these 2-D crystals was determined from the wide-angle X-ray diffraction (WAXD). The structural results acquired from the X-ray scattering/diffraction techniques were consistent with other characterization results including TEM, AFM and NMR.

Structure studies of natural cellulose microfibrils by synchrotron small-angle X-ray scattering

249th National Meeting (2015)

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