Surface characterization of TEMPO-oxidized bacterial cellulose

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 C-13 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 (c) 2013 John Wiley & Sons, Ltd.