Abstract

Wood remains one of the most widely used renewable materials for building and decoration, yet it has well-known vulnerabilities: It readily absorbs moisture, swells and shrinks with humidity changes, is susceptible to fungal and insect decay, degrades under Ultraviolet (UV) light and is flammable. These intrinsic weaknesses limit wood’s use in demanding outdoor and industrial applications, which is why surface coatings have long been the primary strategy for improving performance without altering the bulk material. Over the last five years, the field of wood surface coatings has shifted away from traditional petroleum-based film-forming finishes toward multifunctional, biomimetic and increasingly bio-based systems. Contemporary approaches aim to combine super hydrophobicity with additional protective functions-self-healing, fire resistance, UV shielding and antimicrobial activity-and in some cases retain the natural appearance of wood by maintaining transparency. This review synthesizes the recent literature on these advances. We cover sol-gel and silane chemistries, lotus-inspired micro- and nano-structuring methods, nanocellulose and lignin-based systems, flame-retardant nanocomposites and self-healing or “living” finishes such as fungal bio finishes. Each class of technology offers specific advantages and faces particular limitations in durability, cost and scalability. We also examine a less conventional but promising candidate: hydrophobins. These small, amphiphilic fungal proteins spontaneously assemble at hydrophilic–hydrophobic interfaces to form remarkably robust, single-molecule-thick films. Their unique interfacial behaviour makes them a compelling, genuinely bio-based alternative or complement to synthetic low-surface-energy coating agents. We review the mechanistic basis for how hydrophobin films could protect wood, summarize relevant patents and experimental studies to date and identify the practical barriers to commercial adoption: production cost, UV and abrasion resistance and integration with current finishing lines. On balance, hydrophobins are scientifically credible but still at an early stage of development for large-scale wood protection. Their most plausible near-term role is as part of hybrid or multilayer coating systems, where a hydrophobin interlayer or modifier contributes interfacial adhesion and bio-based hydrophobicity while partnered layers deliver abrasion resistance, UV stability and flame retardancy. We conclude that further targeted research on formulation stability, large-scale production and accelerated weathering tests will be pivotal in moving hydrophobin-containing systems from laboratory demonstrations to commercial practice.

Keywords:Wood Coating; Superhydrophobic Surface; Nanocellulose; Self-Healing Coating; Hydrophobin; Surface functionalization