Improved Hydrophobicity of a Bacterial Cellulose Surface: Click Chemistry in Action.

The vast application potentials of bacterial cellulose (BC)-based materials for developing leather-like materials, wound-healing materials and electronic materials have been realized very recently. Surface functionalization of these materials can help in improvement of certain properties such as water repellency, mechanical strength, and so forth. In this paper, we reported functionalization of BC surfaces using "click" polymerization for the first time. By this methodology, dense aromatic groups have been incorporated for the improvement of hydrophobicity. For comparative studies, various fluorine-based compounds have been introduced using conventional click reactions. The surface-modified BC materials have been confirmed by various spectroscopic methods. Particularly, the chemical structures of the materials were studied by solid-state 13C NMR spectroscopy and attenuated total reflection-infrared spectroscopy. X-ray photoelectron spectroscopy was used to study the elemental composition of the materials. Moreover, the crystallite changes of modified BC surfaces were investigated by X-ray diffraction. Further, the changes in the morphology of the material after functionalization were evaluated by scanning electron microscopy and atomic force microscopy. Finally, water contact angle measurement revealed manyfold increase in hydrophobicity after click polymerization. A video is also provided in the Supporting Information to show the application potential of this material for developing leather-like materials.