Experimental and Analytical Methods in Nanotechnology-Based Wood Surface Treatments: A Systematic Review

The growing application of nanotechnology in wood modification has led to significant improvements in the durability, fire resistance, and biological stability of wood-based building materials, such as glued laminated timber (GLT), as well as related chemical products, including fire retardants and anticorrosion preservatives. While numerous review papers have focused on material performance and functionalisation strategies, a comprehensive analysis of the research methodologies employed in this field remains limited. This review addresses this gap by systematically examining the experimental and analytical methods used in studies on nanomaterial-modified wood surface treatments. Scientific articles published and indexed in the Web of Science and Scopus databases within the last ten years were selected using keywords related to wood, nanotechnology, and surface applications simulating industrial timber treatment processes applied in factories and construction sites. Publications were screened according to predefined inclusion and exclusion criteria. The study selection process was conducted according to the PRISMA methodology, and 74 studies meeting the inclusion criteria were selected for the final analysis. Extracted methodological features were coded and analysed using frequency-based descriptive statistics. Considerable methodological heterogeneity was observed among the analysed studies. Softwood species, TiO2- and ZnO-based nanomaterials, and brushing or immersion treatments represented the most frequently investigated research configurations. Scanning electron microscopy (SEM), often combined with EDS and XRD analyses, occupied a central role within the analytical framework of nanomodified wood research. In contrast, long-term durability assessments, biological resistance testing, and fire-performance evaluations were comparatively underrepresented. The review also revealed substantial variability in the use of testing standards and statistical methods. By linking research methodologies to normative requirements for construction materials, this work provides a methodological framework supporting future research, standardisation, certification, and commercial implementation of nanomaterial-based wood protection systems.