Facile preparation of all cellulose composite with excellent mechanical and antibacterial properties via partial dissolution of corn-stalk biomass

All-cellulose composite (ACC) was directly fabricated by the partial-dissolution welding of cellulose microfibers from agro-residual corn stalks treated with low-concentration ZnCl2 solvent (10-40 %). The solvent infiltrated deeply into nano/micro-scaled pores of cellulose fibers to facilitate the free migration of the disordered chains among the cellulose network while leaving the fiber core undissolved. Then, these disordered chains would entangle and regenerate to serve as a welded layer to bond the undissolved microfibril core in the solvent removal process. Such welding achieved exceptional mechanical (the tensile strength and Young's modulus of 49.9 MPa and 6.6 GPa, respectively), antibacterial (log removal value (LRV) of 4.8 and 3.0 for E. coli and S. aureus, respectively) and biodegradable properties of the multifunctional ACCs. It is worthwhile noting that the excellent antimicrobial effect is attributed to the sufficient contact of these microbes with ZnO NPs that were converted from the residual Zn2+ in ACCs. After five recycling processes, the elimination efficiency could still maintain a high LRV of 2.0-3.8. This high durability of ACC microbicidal activity was originated from strong twining interactions of cellulosic fibrils with in-situ synthesized ZnO NPs. This strategy was proven to be a facile and economical pathway to fabricate functional all-cellulose composites.