Ultrafast dissolution of intact wood via deep eutectic solvent-mediated pathways

Abstract

The efficient dissolution of plant fiber biomass remains a long-standing challenge due to its compact, multi-layered cell wall architecture. Here, we report a universal and energy-efficient two-step dissolution strategy that enables ultrafast (≤2.5 h) dissolution of intact wood and diverse plant fibers. The approach combines an initial swelling step in ZnCl₂–lactic acid (LA) deep eutectic solvent (DES) at 120 °C to enhance solvent accessibility, followed by the addition of ZnCl₂·3H₂O for synergistic coordination-driven dissolution at room temperature, achieving solubilities up to 10 wt%. Structural analyses reveal that ZnCl₂–LA DES markedly expands the cellulose microfibril spacing (from 3.80 to 5.20 nm), increases cell-wall porosity, and selectively cleaves lignin ether linkages, generating highly permeable structures that dismantle the anti-dissolution barrier and enable rapid, coordination-driven dissolution. The strategy significantly lowers energy consumption to 5.01 kJ g⁻¹ while preserving cellulose integrity, with over 70% of the degree of polymerization retained. Upon regeneration, hierarchically entangled nanofiber networks are formed, enabling high-performance materials, including 1D filaments (up to 160 MPa), flexible 2D films (80 MPa, 42% elongation), and lightweight 3D aerogels with excellent thermal stability. This work establishes a scalable and sustainable platform for transforming raw plant biomass into advanced functional materials for green manufacturing and circular bioeconomy applications.