Hydrophobisation of wood surfaces by combining liquid flame spray (LFS) and plasma treatment: dynamic wetting properties

• Published in: Holzforschung Vol. 70; no. 6; pp. 527 - 537
• Main Authors: Moghaddam, Maziar Sedighi, Heydari, Golrokh, Tuominen, Mikko, Fielden, Matthew, Haapanen, Janne, Mäkelä, Jyrki M., Wålinder, Magnus E.P., Claesson, Per M., Swerin, Agne
• Format: Journal Article
• Language: English
• Published: Berlin De Gruyter 01.06.2016; Walter de Gruyter GmbH
• Subjects: Atomic force microscopy; Biodegradation; Chemical composition; Chemistry; cold plasma; Contact angle; contact angle (CA); Dimensional changes; Durability; dynamic wetting; Hexamethyldisiloxane; hexamethyldisiloxane (HMDSO); Hydrophobic surfaces; Hydrophobicity; hydrophobisation; Kemi; liquid flame spray (LFS); Microscopy; Morphology; multi-scale roughness; nano-sized metal oxide (TiO2); Nanoparticles; Organic chemistry; Perfluorohexane; perfluorohexane (PFH); Photoelectron spectroscopy; plasma polymerisation; Polymerization; Repellency; Roughness; superhydrophobicity; Titanium dioxide; Water uptake; Wettability; Wetting; Wilhelmy plate method; Wood; X ray photoelectron spectroscopy; superhydrophobicity; hexamethyldisiloxane (HMDSO); Wilhelmy plate method; hydrophobisation; multi-scale roughness; dynamic wetting; contact angle (CA); nano-sized metal oxide (TiO2); wood; perfluorohexane (PFH); liquid flame spray (LFS); plasma polymerisation
• ISSN: 0018-3830; 1437-434X; 1437-434X
• DOI: 10.1515/hf-2015-0148

The hydrophilic nature of wood surfaces is a major cause for water uptake and subsequent biological degradation and dimensional changes. In the present paper, a thin transparent superhydrophobic layer on pine veneer surfaces has been created for controlling surface wettability and water repellency. This effect was achieved by means of the liquid flame spray (LFS) technique, in the course of which the nanoparticulate titanium dioxide (TiO ) was brought to the surface, followed by plasma polymerisation. Plasma polymerised perfluorohexane (PFH) or hexamethyldisiloxane (HMDSO) were then deposited onto the LFS-treated wood surfaces. The same treatment systems were applied to silicon wafers so as to have well-defined reference surfaces. The dynamic wettability was studied by the multicycle Wilhelmy plate (mWP) method, resulting in advancing and receding contact angles as well as sorption behavior of the samples during repeated wetting cycles in water. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the topography and surface chemical compositions and to elucidate the question how the morphology of the nanoparticles and plasma affect the wetting behavior. A multi-scale roughness (micro-nano roughness) was found and this enhanced the forced wetting durability via a superhydrophobic effect on the surface, which was stable even after repeated wetting cycles. The hydrophobic effect of this approach was higher compared to that of plasma modified surfaces with their micro-scale modification.