Abstract
Acetobacter xylinum, a Gram-negative bacterium, secretes a cellulose nanofiber into the culture medium, and
thereafter the individual secreted nanofibers are assembled to form a 3D network structure as termed "pellicle." The
pellicle has unique properties including high water retention ability, biocompatibility, high strength and so on. Therefore,
a hydrophobic cellulose nanofiber network sheet was attempted to be fabricated by heat-pressing of metal molds having
a micro pattern in order to open further pathways of the pellicle towards potentially versatile materials. From the contact
angle measurements, a heating condition at 130deg for 24 hours was the optimal condition for the treatment. ESCA
analyses indicated that the increase in hydrophobicity was due to introduction of the ether bonds on the surface.
Furthermore, a structural hydrophobic effect such as "Lotus effect" on this sheet was examined by introduction of micro
-lattice patterns onto the surface. Finally, the synergistic effect of the heating and micro-patterning was examined. The
surface of the sheet was more hydrophobic when the two effects were combined together. This successful method could
be generally extended for bio-based materials to provide nano/micro structures with a surface hydrophobic property.
