Superhydrophobic wood surface fabricated by Cu2O nano-particles and stearic acid: its acid/alkali and wear resistance

Reducing the hydrophilic nature of wood could enhance dimensional stability and improve life cycle performance. Masson pine and pecan wood were modified to create superhydrophobic, self-cleaning functions by spray-coating with Cu2O nano-particles (Cu2O NPs)/phenol formaldehyde (PF) resin mixed solution followed by immersion in a stearic acid ethanol solution. Two types of Cu2O NPs, derived from different concentrations of copper chloride (CuCl2) were evaluated for their ability to improve hydrophobicity of wood surface. A special petal-shaped structure on the edge of Cu2O NPs was found on modified pecan wood, and water contact angles (WCA) of both kind of modified wood reached around 155 degrees and sliding angles (SA) less than 10 degrees. Meanwhile, low liquid permeability and excellent repellency to aqueous solutions with pH =1 to 13 were achieved. The critical WCA around 150 degrees was also maintained on modified wood surfaces after being immersed in strong acid (pH = 2) and strong alkali (pH = 12) solutions for 12 h. Furthermore, remarkable mechanical durability was obtained after harsh abrading test, which could be attributed to the high bond strength from cured PF resin adhesive. Such highly waterproof, acid/alkali resistant and hard-wearing superhydrophobic surface must have potential to be widely applied in wood products industry.

Automated summary

The study demonstrated the creation of superhydrophobic and self-cleaning functions on Masson pine and pecan wood surfaces by spray-coating with Cu2O nano-particles/phenol formaldehyde resin mixed solution. The modified wood showed water contact angles of around 155 degrees and excellent repellency to aqueous solutions with pH = 1 to 13, making it highly waterproof, acid/alkali resistant, and hard-wearing.