Surface characterizations of bamboo substrates treated by hot water extraction

Environment Scanning Electron Microscopy (ESEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology and chemical changes on both the interior and exterior surface of bamboo (Dendrocalamopsis oldhami) substrates treated by hot water extraction. ESEM results showed the visible changes between exterior and interior surface of the treated substrates, in where spherical droplets did not extensively appear on both the surfaces at start of the pretreatment; nevertheless the droplets formation on the exterior surface occurred more rapidly than that of the interior surface. Results from XPS examination that the increase of C1 (C–C, C–H) concentration and decrease of O/C ratio and O1 (CO) concentration of the samples on the both surfaces further demonstrated that both surfaces consisted of increasing amount of lignin as the extraction continued, especially for exterior surface. The O/C ratios finally reached to a level-off value with exterior surface 0.34 and interior surface 0.37.