Bioinspired superhydrophobic-superhydrophilic convertible film based on anisotropic red blood cell-like particles with protuberances

A novel morphology structure of red blood cell-like (RBC) particles with protuberances (P-RBC) was prepared through dispersion polymerization process. Based on these particles, a superhydrophobic coating film with strong water adhesion and a superhydrophilic film was fabricated depending on orientation of particles during self-assembly progress. The superhydrophobic coating film with water contact angle (CA) of 163.6 degrees was fabricated when the direction of particle cavity was facing-down. Strong water adhesion was resulted from the larger micro-nano structure of particles. Waterdrop tightly attached to the surface of the coating film even if it was taken upside down. Whilst if the cavity of particles was upward, the coating film was transferred to be superhydrophilic of CA of 3.8 degrees under co-efforts of storage ability of cavities, penetration capacity of channel formed by well-ordered particles, and increased surface roughness. This work gives that anisotropy colloidal particles have potential application with their superior wetting characteristics in many fields, such as material transfer process, waterproof protection and oil-water separation.