Fabrication Of Several Kinds Of Tunable Wettability Surfaces On Copper Substrate

Wettability is one of the most important properties of the solid surface. Due to the correlation with a surface tension gradient, wettability control provides a more flexible and efficient way for wide applications such as self-cleanness, discrete liquid droplet manipulators or tunable optical lenses. In many cases, tethering of polymer chains onto a solid substrate provides an expedient method for modifying the surface properties of the substrate. Compared with other surface assembly techniques, surface-initiated radical polymerization has more advantages, including controlled thickness of polymer film and polymer molecular weights and molecular weight distributions, firm combination of the polymer film with the substrate, and ordered molecular assembly. In this thesis, smart copper surfaces with tunable wettability have been prepared.(1) An ionic liquid monomer 1-(4-vinylbenzyl)-3-butylimidazolium hexafluorophosphate (VBIm-PF6) was synthesized according to a slight modification method of the reference and characterized by proton and carbon nuclear magnetic resonances. The crystal and molecular structures were measured by X-ray single crystal diffraction.(2) After a micro/nanoscale structural flower-shape CuO surface was constructed by a chemical oxidation on copper substrate, polymeric ionic liquid PVBIm-PF6 was successfully grafted on the surface using a surface initiated NMRP polymerization. The tunable wettability of the poly (ionic liquid) modified surface can be easily achieved by sequentially exchanging their counter anions.(3) Superhydrophobic Cu surfaces were prepared by immersing a copper plate into a methanol solution of fatty acids at ambient temperature. This superhydrophobic film comes from the formation of a micro/nano hierarchical structure. It was found that the superhydrophobicity relies on micro/nano hierarchical structure and the modification of long fatty acid chains which have low surface free energy. This superhydrophobic film has a high water contact angle (CA) and a low sliding angle. And the formation mechanism of the superhydrophobic films was also proposed.