Construction of a superhydrophobic wood surface coating by layer-by-layer assembly: Self-adhesive properties of polydopamine

To prevent moisture deformation, water swelling, severe mildewing, and decay due to the biodegradation of wood during outdoor use, a superhydrophobic wood surface coating was prepared by a layer-by-layer assembly method using polydopamine (PDA) and 1H,1H,2H,2H-perfluoro-decyl trichlorosilane (PFDTS). Due to its self-adhesive properties, PDA was used as an intermediate layer to connect the wood and PFDTS. PDA was first deposited on the wood surface to form a highly crosslinked granular structure that improved the surface roughness of wood. The wood surface was further modified by low-surface-energy PFDTS, and the wood after PDA deposition was superhydrophobic with a water contact angle (WCA) of 154°. The particle size of nano-PDA, as measured by laser particle size analysis, remained in the range of 0.57–2.73 μm. The surface morphologies of PFDTS/PDA coatings on glass plates were detected by EDF 3D microscopy, FE-SEM, and AFM. The bonding mechanism between coating components and wood surfaces was investigated by energy-dispersive spectroscopy, FT-IR spectroscopy, and X-ray photoelectron spectroscopy. The hydrophobic coating underwent rapid restoration and was resistant to both acidic and alkaline solutions (pH 2–12). This work provides a simple way to endow superhydrophobic properties to wood and has potential multifunctional applications for wood protection and new products.