Self-assembly of cellulose nanocrystals on flexible fabric via a metal coordination strategy for versatile applications

Cotton fabric is widely found in nature, and its outstanding breathability, flexibility, and rich surface groups have encouraged material scientists to investigate it. Self-assembly on the surface of cotton fabrics is an ingenious strategy for developing value-added textiles with special functionalities. This study reports a facile, low-cost technique for directing modified cellulose nanocrystal (CNC) self-assembly by copper ions on the surface of cotton fabrics. Uniform dense sea urchin-like modified CNC agglomerates were formed on the fibres surface, which greatly increased itsspecific surface area. Due to the involvement of Cu2+ in the chelation process and the high specific surface area of the micro-nano structure, the antibacterial effect of this coated fabric was up to 99.9 %. Meanwhile, its water stability was greatly improved by secondary treatment with perfluorooctylethyltrimethoxysilane, extending the potential applications of the self-assembled coating. The results showed that the water contact angle of the coated fabric reached 160° ± 0.5°, and the construction of the micro-nano surface structure enabled it to absorb 3 and 5 times of its own weight of n-heptane and carbon tetrachloride. In addition, the coated fabric also has excellent mechanical stability and chemical durability, shows self-cleaning, oil-water separation and many other properties. At the same time, the breaking strength and wearability of the fabric have been improved after the nano-organic coating finishing. Combining the advantages of flexible fabrics and organic nanofillers, coated fabric is expected to bring traditional textiles to the fore in areas such as stain protection, safety, and health care.