Engineering robust bio-based 3D structures from corn stalk pith through a sustainable route to nano-micro structured...

Porous three-dimensional (3D) structures with excellent resilience have attracted considerable attention across various fields, including construction and energy storage. However, current fabrication methods often rely on bottom-up approaches, leading to complex production processes and environmental concerns. In this work, we develop the bio-based 3D structures that preserves the intrinsic cellular microstructure of biomass via cell wall engineering under mild conditions. Corn stalk pith (CSP), an agricultural waste, is sequentially treated with dilute acid and an inorganic salt solvent, resulting in the 3D structures with excellent compressive resilience, even at a strain of 70 % in extreme environments. The enhanced compressive resilience is primarily attributed to the reduction of rigid lignin content, the intrinsic cellular microstructure, and the thickened hydrogel cell wall. Metal ions introduced through the salt solvent conferred ionic conductivity to the material, enabling a detection limit as low as 0.1 kPa. These properties allow the bio-based sensor to precisely monitor various human activities by translating compressive deformation into reliable signals. This work presents an innovative strategy for creating naturally porous and elastic materials with exceptional structural stability using agricultural wastes. These materials hold potential applications in oil-water separation, flexible electronics, and thermal insulation.