Investigation of the supramolecular structure of never dried bacterial cellulose

Supramolecular structure of initially wet bacterial cellulose of Acetobacter xylinum has been investigated by X‐ray scattering including synchrotron radiation, transmission electron microscopy, and 13C‐CP/MAS‐NMR‐spectroscopy. As a result a model is given of never dried swollen microfibrillar ribbons consisting of 5 to 12 waterfree Iα‐crystalline subunits with a cross‐section of about 7 nm × 13 nm and of water solvating the subunits. Lateral aggregation of these crystalline units was found along the smaller (110)‐lattice planes with a layer of water between adjacent crystallites. The NMR‐spectrum of wet bacterial cellulose exhibits an additional C‐1 line component indicating cellulose‐water interactions. During drying lateral dimensions of the microfibrillar ribbons, crystallite sizes, as well as the overall crystalline order decrease, whereas the Iα/Iβ‐ratio of about 80/20 remains approximately unchanged. Conclusions were drawn with regard to the early states of structure formation of bacterial cellulose.