The effect of glide plasma with methane gas on the hydrophobicity of poplar wood surface

The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma treatment with methane was used to hydrophilize the surface of the wood and create weathering resistanc. The poplar wood (Populus deltoides) were exposed to glide plasma under various laboratory conditions such as time of exposure, voltage, frequency, distance between electrodes as well as flow of inlet gas and outlet gas with methane inside a reactor. Then the surface properties of wood were studied using scanning electron microscope (SEM), measurement of water drop contact angle, ATR‐FTIR spectroscopy, roughness survey, and colorimetry. The specimens were then subjected to the accelerated weathering using the Gardner weathering wheel and their properties were checked again. The SEM images showed that the plasma creates a warty layer on the surface of the wood which could be due to the deposition of new materials or the physical effects of plasma (surface etching). The plasma treatment significantly increased the contact angle of the water droplet on the surface of the treated samples. The treated samples had a higher surface roughness than the control samples. The surface of treated samples was generally darker than the control. After exposure to the accelerated weathering, the effect of treatments on surface hydrophobicity was largely lost. The treated samples had less roughness changes than the control after exposure to the weathering, and also their dark color changed to silver-gray. The use of glide plasma with methane gas showed the great potential for creating hydrophobic surfaces on the wood, but it did not last long and lost its effectiveness due to weathering.