One-Step Approach to the Growth of ZnO Nano-/Microrods on Cellulose toward Its Durable Superhydrophobicity

Superhydrophobic surfaces have aroused great attention to fundamental and scientific researches. However, they have poor durability when they are exposed to a condition of high temperature or external forces. Herein, a durable superhydrophobic cellulose film against extreme high temperature and mechanical force is reported. ZnO nano- and microrods are constructed on cellulose using an effective, simple, and environmentally benign one-step hydrothermal method without any crystal seeds or morphology controlling agents. After being modified with stearic acid, the cellulose film becomes superhydrophobic with a static contact angle of 154.1 degrees and rolling angle of 6.9 degrees. The superhydrophobic cellulose film shows excellent water-repellent property even under dynamic water pressure, while it exhibits oleophilic nature under water, which can solve water pollution caused by heavy oil residuals. It is further found that it displays durable superhydrophobicity even if heated at 200 degrees C for 1 h or strongly scratched by knife. And heat treated films have better stability of superhydrophobicity under extreme condition with pH region from 3 to 11. These properties facilitate its applications of harsh conditions.