Chemical modifications and characteristic changes in bacterial cellulose treated with different media

Bacterial cellulose membranes have attracted a great deal of attention as novel biomedical materials. In this paper, bacterial cellulose was treated with acidic, alkaline, and redox solutions to investigate the subsequent changes in the characteristics of the cellulose. The chemical structure, crystalline state, water-holding capacity, and micromorphology of each modified BC were characterized by FTIR, SEM, and XRD. After these treatments, the intermolecular or intramolecular hydrogen bonds of the BC were broken and the water bound to the BC was released from the BC hydrogel. During these processes, the crystallinity and surface morphology of the BC were also modified. Meanwhile, the crystalline form of the BC changed from cellulose I to II in alkaline medium. In particular, the BC nanofiber hydrogel broke into floccules when treated with highly concentrated NaOH solution at a temperature of −5 °C, but these floccules congregated into a bulk state again after removing the NaOH.