In situ construction of antifungal surface on cellulose by ternary deep eutectic solvent and its application to Phyllostachys edulis

Cellulosic materials have been widely applied in various fields such as construction, medicine, and new energy. However, the inherent structure of cellulose, composing of multiple hydroxyl groups, is highly susceptible to fungal degradation, thereby significantly limiting its high-value applications. Existing antifungal measures often fail to balance environmental friendliness and convenient preparation. Inspired by the antifungal properties of sulfated polysaccharides, this study utilized a deep eutectic solvent (DES) composed of sulfamic acid/1,3-propanediol/benzenesulfonic acid (S/P/B DES) to construct an intrinsically antifungal structure on cellulose via sulfation, making the preparation process more environmentally friendly and straightforward. Under the influence of the S/P/B DES, the hydroxyl groups at the C2, C3, and C6 positions of the cellulose pyranose ring underwent sulfation reactions, which imparted negative charge to the surface. The electrostatic interactions rendered the cellulose molecular chains more dispersed and amenable to rearrangement, combined with the acidolysis of the amorphous regions and the dissolution of the crystalline regions by the S/P/B DES, the cellulose chains spontaneously reorganized into a more compact structure. Using Material Studio demonstrated this structure would provide additional binding sites for fungi, thereby facilitating their adsorption and subsequent degradation, as a result, the antifungal performance of cellulose was significantly improved. Additionally, considering that Phyllostachys edulis contains over 50 wt% of cellulose and is highly susceptible to the degradation from fungal, which severely reduces its application value, this study further explored the potential surface application of the S/P/B DES in bamboo’s antifungal treatment.