The surface functionalisation of wood and cellulosic fibres using natural components

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School of Chemical Technology | Doctoral thesis (article-based) | Defence date: 2017-04-21
Degree programme
63 + app. 69
Aalto University publication series DOCTORAL DISSERTATIONS, 55/2017
This work focused on developing surface treatments for various cellulosic materials, including wood, cellulose nanofibrils (CNF), and natural textiles (cotton and linen). For this purpose, several approaches were developed, aiming at various improvements depending on the type of substrate. Some components were created specifically for this work, including amphiphilic galactoglucomannan (GGM) derivatives and an aqueous carnauba wax dispersion. On wood, non-continuous coatings were assembled, made of natural wax particles alone or combined with UV-absorbing additives. When wax particles were used alone, the performance of the coated wood was compared to a continuous wax film and commercially available coatings (lacquer, linseed oil). The treatment with particles enhanced the hydrophobicity of the wooden surface and its moisture buffering performance. Additionally, it is known that protection from the degrading effect of UV light is as important as protection against water. Therefore, zinc oxide nanoparticles were incorporated together with wax particles into multilayer coatings through layer-by-layer (LbL) deposition. The multilayers increased the roughness of the wooden surface and provided UV-absorbing properties. Moreover, the coated wood was superhydrophobic, yet the moisture buffering was preserved and even enhanced. On CNF, galactoglucomannan derivatives with different hydrophobic tails were adsorbed. The derivatives were synthesised using naturally occurring fatty acids or polydimethylsiloxane as hydrophobic blocks. The hydrophobic moieties did not hinder the adsorption on cellulose, and all GGM-derived materials were found to adsorb irreversibly. However, the use of hydrophobic blocks with high molar mass was required in order to overcome the inherent hydrophilicity of the GGM molecule, and increase the hydrophobicity of the surface. Moreover, inspired by the promising results achieved on wood, wax-containing multilayers were assembled on CNF and textiles. Here poly-L-lysine (PLL) was utilised instead of zinc oxide as the cationic counterpart. Two bilayers were sufficient to reduce the sensitivity towards water and switch surfaces from being highly hydrophilic to hydrophobic, or superhydrophobic. In addition, studying the LbL assembly with quartz crystal microbalance revealed that the adsorption of the wax particles increased with the pH of the PLL solution. Nevertheless, the oxygen permeability of the CNF films and moisture sorption of textiles were preserved in all cases. Having these properties, the enhanced cellulosic materials could be used in advanced applications, like smart packaging, passive climate control systems, and breathable superhydrophobic clothing for sports and outdoors.
Supervising professor
Österberg, Monika, Associate Prof., Aalto University, Department of Bioproducts and Biosystems, Finland
Thesis advisor
Österberg, Monika, Associate Prof., Aalto University, Department of Bioproducts and Biosystems, Finland
surface modification, wax particles, layer-by-layer assembly, hydrophobicity, cellulose nanofibril films, wood, cellulosic textiles
Other note
  • [Publication 1]: Lozhechnikova Alina; Vahtikari Katja; Hughes Mark; Österberg Monika. 2015. Toward energy efficiency through an optimized use of wood: The development of natural hydrophobic coatings that retain moisture-buffering ability. Energy and Buildings, 105, 37-42.
    DOI: 10.1016/j.enbuild.2015.07.052 View at publisher
  • [Publication 2]: Lozhechnikova Alina; Bellanger Hervé; Michen Benjamin; Burgert Ingo; Österberg Monika. 2017. Surfactant-free carnauba wax dispersion and its use for layer-bylayer assembled protective surface coatings on wood. Applied Surface Science, 396, 1273-1281.
    DOI: 10.1016/j.apsusc.2016.11.132 View at publisher
  • [Publication 3]: Lozhechnikova Alina; Dax Daniel; Vartiainen Jari; Willför Stefan; Xu Chunlin; Österberg Monika. 2014. Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans. Carbohydrate Polymers, 110, 163-172.
    DOI: 10.1016/j.carbpol.2014.03.087 View at publisher
  • [Publication 4]: Forsman Nina; Lozhechnikova Alina; Khakalo Alexey; Johansson Leena-Sisko; Vartiainen Jari; Österberg Monika. Hydrophobic, simple and sustainable coating of CNF films and cellulosic textiles based on layer-by-layer deposition of poly-Llysine and natural wax particles. Manuscript submitted to Carbohydrate Polymers