In this study, we focused on the surface character of bacterial cellulose (BC) before and after oxidation mediated by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO).Solid‐state 13C NMR, XPS, SEM, contact angle and surface free energy analyses were performed to investigate the effects of various parameters (reaction time and oxidant and catalyst concentrations) on the surface composition, morphology and polarity of the BC. The results provided by the combined use of these techniques showed that hydrogen bonds were disrupted on the BC surface after carboxylation occurred; therefore, the surface of oxidized BC was rougher than that of the original BC, and the surface free energy, especially the polar components, increased after oxidation. Copyright © 2013 John Wiley & Sons, Ltd.

A partially C6-carboxylated bacterial cellulose (BC) with a high carboxylate content was prepared in a bromide-free system by using 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO) as a catalyst. ART-FTIR, X-ray diffraction, solid 13 C-NMR, TEM analysis, and reaction kinetics measurements were performed to investigate the oxidation reaction of BC. Results show that C6 carboxylate was formed selectively on the microfiber surface without disrupting its highly ordered nanocrystalline structure. Given the extremely low accessibility of hydroxyl groups in D-anhydroglucopyranose units, the reaction can be described by second-order kinetics with very low reaction rate constants. pH exhibited a significant influence on the oxidation of BC and a higher activity at C6 was observed in a neutral medium.