Hierarchical structure of microbial cellulose and marvelous water uptake, investigated by combining neutron scattering instruments at research reactor JRR-3, Tokai.

We discuss microbial cellulose (MC) produced by Acetobacter Xylinum and its metabolism related to the bacterium body structure on a basis of knowledges obtained by the small-angle scattering method with combining different spectrometers. MC is a supra-molecule system impregnated with a huge amount of water about 99% by weigh. In the previous literature [ Eur. Phys. J. E , 2008 and Macromol. Symp. 2009], we elucidated that 90% of total water is accumulated in non-crystalline bundle causing concentration fluctuations. In this paper, we develop our arguments by newly adding the knowledges on (i) the hierarchy in a bacterium body studied by SANS & USANS and (ii) the non-crystalline local structure in as-produced MC in a culture solution, confirmed by neutron diffraction with polarization analyses. As a control to emphasize the peculiarity of MC, we compare MC to a synthetic polymer gel of poly(N -isopropylacrylamide) (PNIPAAm) in a swollen state. Consequently, we conclude that a mechanism of excellent water absorption found for MC is attributed to capillarity related to hierarchically preserved non-crystalline domains, whereas tight hydration onto a monomer unit via a hydrogen bond is crucial to result in high water absorption for the PNIPAAm gel. Image 1 • In the previous literatures [ Eur. Phys. J. E , 2008 and Macromol. Symp. 2009], we elucidated that 90% of total water is accumulated in non-crystalline bundle in microbial cellulose (MC) produced by Acetobacter Xylinum. • In this paper, we developed our arguments by newly adding the knowledges on (i) the hierarchy in a bacterium body studied by SANS & USANS and (ii) the non-crystalline local structure in as-produced MC in a culture solution, confirmed by neutron diffraction with polarization analyses. • As a control, we studied a synthetic polymer gel of poly(N -isopropylacrylamide) (PNIPAAm) in a swollen state. • A mechanism of excellent water absorption of MC is attributed to capillarity related to hierarchically preserved non-crystalline domains, whereas tight hydration onto a monomer unit via a hydrogen bond is crucial for high water absorption for the PNIPAAm gel. [ABSTRACT FROM AUTHOR]