Wettability And Adhesion Properties Of Highly Ordered Honeycomb Prous Films

The wettability of solid surfaces is a very important property that is closely related to a lot of physical and chemical processes such as absorbing, wetting, bonding, dispersing and friction, which makes it important in both scientific research and practical applications. Highly ordered honeycomb porous films prepared by the breath figure method have regular structure and uniform pores, leading to potential applications as optical materials, filtration membranes, cell culture substrates, templating materials, and superhydrophobic surfaces. Here, we used honeycomb films from PS-b-PDMAEMA as substrates and investigated the surface modification to modulate the wettability and adhesion property. Our specific studies are concentrated on the following aspects:1. Honeycomb films and the corresponding pincushion-like surfaces, which were fabricated by peeling off the top layer of the honeycomb films, were coated with poly(dopamine) followed by the reaction with 1H,1H,2H,2H-perfluorodecanethiol for constructing superhydrophobic surfaces. To obtain optimal experimental conditions, some factors, including deposition procedures, reaction time and concentration of the thiol, were studied in detail. And, the surface morphology and chemical composition of the films were evaluated. The wettability and adhesion properties of the honeycomb films and pincushion-like surfaces before and after surface modification were studied. Results indicated that superhydrophobic surfaces with tunable adhesive property can be fabricated by the proposed procedure. Moreover, no-loss transportation of water droplets was realized on the surfaces.2. Co-deposition of dopamine with hydrophilic polyethyleneimine (PEI) was performed on honeycomb films and the pincushion-like surfaces to investigate wettability changes of the porous surfaces. Films with different surface hydrophilicity were realized by adjusting co-deposition time and PEI concentration. It is found that the co-deposition layer distributed uniformly on the surfaces, and the morphology of the porous surfaces remained. Moreover, by simply controlling the co-deposition time, surfaces in Cassie-Baxter state or Wenzel state can be obtained; as a result, site-specific deposition was achieved on the honeycomb films. The results are useful in understanding the wetting transition on porous surfaces, providing a pathway toward to site-specific modification of the films.