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F. Liebner, E. Haimer, M. Wendland, M.-A. Néouze, M. Litschauer, A. Hardy-Dessources, J. Nedelec, K. Schlufter, P. Miethe, A Potthast, T. Rosenau:
"Aerogels from bacterial cellulose: Preparation, characterization and modification of dimensionally stable, ultra-lightweight cellulosic bodies.";
Talk: 239th ACS National Meeting, San Francisco, CA, United States; 2010-03-21 - 2010-03-25.

Bacterial cellulose (BC) produced by the gram-negative bacterium Gluconacetobacter xylinum was demonstrated to be an excellent native source for preparing shaped ultralightweight cellulose aerogels. The facile procedure comprises thorough alkaline pretreatment, washing and sterilization of the aquogel, quantitative solvent exchange, and subsequent scCO₂ drying (40°C, 100 bar).
Drying experiments revealed that BC alcogels feature a surprisingly high dimensional stability upon scCO₂ drying compared to similar gels obtained from commercial pulps via dissolution/regeneration/scCO₂ drying sequences. ScCO₂ dried BC aerogels were furthermore found to be quantitatively re-wettable (99.02±0.10% H₂O, n=10) whereas the equilibrium water content of freeze-dried samples was lower (97.47±0.21%, n=3).
SEM, ESEM, nitrogen adsorption experiments at 77 K, and thermoporosimetry revealed showed an open-porous cellulose network structure with a high percentage of macro- and mesopores at hitherto unparalleled, low densities of less than 8 mg cm^-3. The mechanical stability and other properties have been tuned by chemical modification.