Structure and mechanisms of foam-like bamboo parenchyma tissue

The increased awareness of environmental problems has shifted the attention from synthetic polymer porous materials to natural plant porous materials like bamboo parenchyma tissue to develop functional materials. However, the neglect of the inherent structure and property of plant porous materials leads to insufficient development and utilization of their natural advantages. Here, we investigated the fine structure and mechanisms of bamboo parenchyma tissue, which has multiple high-quality properties like energy-absorbing and toughening, to provide a basis for their wide utilization in porous materials. Results showed that bamboo parenchyma tissue was a foam-like porous material with sufficient strength, high porosity and low density. It was composed of cell walls and four types of three-dimensional polyhedral pores converging in space. The total natural porosity was up to 78.80%. The cell walls exhibited a three-zone strength distribution with an average solid cell wall strength of 75.84 MPa, due to their cocoon-like closed microfibrils patterns, chemical compositions and pits characteristics. The high porosity and weakening of transition zone and cell end wall helped to absorb energy. This study provides ideas for the application of bamboo parenchyma tissue in cushioning energy-absorbing foam materials and porous material templates and for the biomimetic design of environmentally friendly porous materials.