Towards the development of superhydrophobic carbon nanomaterial coatings on wood

• Published in: Progress in organic coatings Vol. 125; pp. 23 - 31
• Main Authors: Łukawski, Damian, Lekawa-Raus, Agnieszka, Lisiecki, Filip, Koziol, Krzysztof, Dudkowiak, Alina
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-12-2018; Elsevier BV
• Subjects: Abrasion; Abrasives; Carbon; Carbon black; Carbon nanotubes; Coatings; Contact angle; Graphene; Hydrophilicity; Hydrophobic coating; Hydrophobic surfaces; Hydrophobicity; Immersion coating; Nanomaterials; Rose petal effect; Sandpaper; Surface energy; Textiles; Water absorption; Wood; Wood fibers; Carbon nanotubes; Hydrophobic coating; Wood; Graphene; Rose petal effect
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2018.08.025

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•Graphene and carbon nanotubes introduced superhydrophobicity to naturally hydrophilic wood.•The coating was performed by simple inexpensive and industrially viable methods.•“Rose petal” effect based model was proposed to explain wettability of CNM coated wood.•Water repellant, CNM coating on wood particles may also find applications in wood based composited.
Carbon nanomaterials (CNMs) have recently been used to form superhydrophobic coatings on metals, synthetic polymers or textiles. Here we investigate the possibility of using carbon black (CB), graphene (Gr) and carbon nanotubes (CNTs), as water repellent agents on naturally hydrophilic wood. We show that it is possible to form homogeneous CNM coatings on any type of wood via simple methods of drop casting and dip coating, using CNMs dispersed in organic solvents or water. Contact angle measurements of wood coated with only 0.05 g/m2 CNTs and 0.25 g/m2 Gr gave the results exceeding 130°, indicating apparent hydrophobicity. Yet, high adhesion of the droplets was observed, simultaneously suggesting a “rose petal” type of superhydrophobic behavior. That may be explained by the formation of micro-nano architectures in which low surface energy CNMs deposited on microrough surface of wood cause superhydrophobicity. Yet, due to heterogeneity of wood, some part of hydrophilic surface is still uncovered, resulting in high adhesion of water. Finally, although Gr and CNT were only physically bond to wood surface, the hydrophobic properties of CNM coatings were maintained after sandpaper abrasion test. Moreover, wood fibers and particles covered with Gr showed the decrease of water absorption equal 98% and 87%, respectively.