An investigation of the fluid-holding cavities in a lignocellulose-based bamboo matrix via a combined X-ray microtomography and proton time-domain NMR approach

Abstract

Bamboo (Dendrocalamus giganteus) is a functionally graded material with well-organized hierarchical structures. Its micrometer-sized vascular bundles and parenchymatic living cells allow an efficient upward flow of water and nutrients, endowing the organism with remarkably fast growth. As demonstrated recently, the hollow microstructure channels can be explored as a natural template for microfluidics applications in chemical synthesis, analytical detection, solar steam generation, and electrochemical devices. Thus, the knowledge of the kinetics of the imbibition and spatial distribution of fluid through the microcavities of the bamboo vegetal tissue became of interest. Here, we employed a combination of X-ray microtomography (µCT) and proton time-domain NMR (TD-NMR) to identify, measure, and investigate empty volumes embedded in the bamboo’s tissue as experienced by different organic and inorganic fluids, namely dimethyl sulfoxide (DMSO) and distilled water (H2O). Results have shown that the extensive communication between the voids (parenchymal cells and vascular channels) does not prevent the individuation of fluid reservoirs with different behaviors, as evidenced by the H2O desorption profile. Bamboo parenchyma was the tissue that retained more residual H2O after desorption. The difference in wettability of bamboo tissues by DMSO and H2O was detected. Graphical abstract