The fabrication and property of hydrophilic and hydrophobic double functional bionic chitosan film

A new kind of hydrophobic bionic chitosan film was fabricated by simulating the surface structure of lotus leaf. The titanium oxide nanotube array was used as templates. Scanning electron microscopy (SEM) images show that one side of this films have nano-scale rough surface with spherical protrusions alike the surface of lotus leaf. The diameter of the protrusions is about 100 nm, which is equal to diameter of the titanium oxide nanotube. The water contact angle of chitosan films is up to 120 degrees and it is hydrophobic. The other side of the film is flat and the contact angle is 70 degrees. That indicated that the hydrophilism of natural materials is connected with the surface structures. The double functional chitosan films, one side is hydrophilic, the other is hydrophobic, can be made by an easy method. This method is non-toxic and clean. The double functional chitosan film will improve the application of chitosan films in medicine.