Fabrication of Superhydrophobic Wood Surface by Etching Polydopamine Coating with Sodium Hydroxide

Abstract

Superhydrophobic treatment of wood surfaces can effectively prevent the contact between the external moisture and wood, which improves the service life of the wood. In this study, different rough surfaces of wood were constructed, derived from the self-polymerization of dopamine (DA) in weak base solution to form a polydopamine (PDA) coating and the deprotonation of the PDA coating in a strong base solution. Furthermore, octadecyltrichlorosilane (OTS) was used as a low-surface-free-energy agent to modify rough surface in order to prepare superhydrophobic woods: Wood@PDA–NaOH–OTS and the Wood@PDA–NaOH/SiO2–OTS. The contact angles (CAs) and sliding angles (SAs) of the resulting superhydrophobic woods were tested. The results showed that the CA and SA of the Wood@PDA–NaOH–OTS were 151° and 4.8°, respectively; the CA and SA of the Wood@PDA–NaOH/SiO2–OTS were 155.1° and 5.0°, respectively. Surface electron microscopy (SEM) images presented that NaOH successfully etched the PDA coating, and the roughness was further improved by adding nano-SiO2. Atomic force microscope images (AFM) revealed that the nano-SiO2 particles could effectively provide nanolevel roughness, which was beneficial to the wood’s superhydrophobic properties. In addition, the obtained superhydrophobic wood possessed strong surface stability and anti-loss property, as well as resistance to acid-base solution and organic solvent.

Improving Hydrophilicity and Adhesion of PDMS through Dopamine Modification Assisted by Carbon Dioxide Plasma

“…Many researchers have done a lot of research on increasing the hydrophilicity and surface energy of PDMS and enhancing its adhesion and functionalization [7][8][9]. It is reported that dopamine (DA) can be codeposited into a nano-thin layer of poly(dopamine) (PDA) on the surface of the material through covalent bonds, hydrogen bonds, metal chelation, and π-π interaction under alkaline conditions, thus improving the surface energy and adhesion of the material [10][11][12]. Although acrylic acid, etc., can also be used as co-deposited coatings to improve surface energy and adhesion, the process is mostly time-consuming, relies on relatively complex setups, and is often limited to certain substrate chemistries and types of target molecules [13].…”

Research Progress on the Improvement of Flame Retardancy, Hydrophobicity, and Antibacterial Properties of Wood Surfaces

“…Wood is a popular material for furniture and floor manufacturing as well as other industries since it is inexpensive, simple to produce, beautifully patterned, naturally renewable, and low-carbon [ 44 , 72 , 73 , 74 , 75 ]. However, wood cell walls are composed of cellulose, etc., and the hydroxyl groups on its branch chains combine with water to create hydrogen bonds, resulting in the wood itself being significantly hydrophilic [ 76 , 77 ]. It is prone to corrosion in a humid environment, resulting in cracking, mildew, greatly reducing the durability of wood, resulting in resource waste, and economic losses [ 78 , 79 , 80 ].…”

Surface physical structure and durability of superhydrophobic wood surface with epoxy resin

“…Meanwhile, the application of superhydrophobic modification for wood is proposed to overcome the above challenges. The wood surface was endowed with unique wettability and improved the functional properties, such as water resistance, dimensional stability, etc., which further broadens wood multifunctional usage (Yi et al 2020).…”