Experimental and molecular dynamics simulation study of chemically stable superhydrophobic surfaces

Experimental and molecular dynamics simulation study was used to clarify the hydrophilicity of substrate surfaces and hydrophobicity of as-prepared surfaces at molecular level. First, an easy one-step approach was utilized to construct superhydrophobic surfaces on different substrates such as steel, aluminum, glass, and silicon wafer. The superhydrophobicity of as-prepared surfaces were contributed to the fluorinated compositions and microstructures. A fluorinated surface was constructed as a model of the as-prepared superhydrophobic surface. Molecular dynamics simulations were utilized to elucidate the anti-wetting mechanism of as-prepared fluorinated surfaces on aluminum substrates. Compared with the compact hydrated layer on the aluminum substrate, the hydrated layer on the fluorinated surface were broader with a lower intensity, confirming the lower attractive force between surface and water molecules. The decreased van der Waals interaction with water molecules contributed to the hydrophobicity of the fluorinated surface. While, in an alkaline solution, the electrostatic interaction had a negative impact on hydrophobicity of a fluorinated surface.