Surface Structure Patterning for Fabricating Non-fluorinated Superhydrophobic Cellulosic Membranes

Superhydrophobic surfaces have attracted great interest in both scientific research and industrial applications. Patterned nanocellulose membrane surfaces were fabricated by a simple pressing process. After chemical modification with non-fluorinated and low-cost industrial chemicals, such as alkyl ketene dimers (AKD), wax, and isocyanate, some nanocellulose membranes showed water contact angles >150°. The combination of microsized pattern and nanosized cellulose fibers created a hierarchical structure that contributed to the superhydrophobic properties. SEM and optical microscopy were used to characterize the fiber network and hierarchical structures. Wetting experiments showed that water droplets roll off the cellulose membrane with fabricated pillar size lower than 100 μm after chemical modification with AKD, wax, or isocyanate. The process used in this superhydrophobic cellulose membrane fabrication is simple, cost-effective, and amenable to scale up so it has potential to be used as a liquid packaging material