Innovative Treatment of Ancient Architectural Wood Using Polyvinyl Alcohol and Methyltrimethoxysilane for Improved Waterproofing, Dimensional Stability, and Self-Cleaning Properties

Abstract

This study introduced a novel two-step treatment to enhance the waterproofing, dimensional stability, and self-cleaning capabilities of ancient architectural wood. The process was initiated with the immersion of wood in an organic hybrid sol, composed of an acidic methyltrimethoxysilane (MTMS)-based silica sol and polyvinyl alcohol (PVA), which effectively sealed the wood’s inherent pores and cracks to mitigate degradation effects caused by aging, fungi, and insects. Subsequently, the treated wood surface was modified with an alkaline MTMS-based silica sol to form a functional superhydrophobic protective layer. The modification effectiveness was meticulously analyzed using advanced characterization techniques, including scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The results demonstrated substantial improvements: the modified wood’s water contact angle (WCA) reached 156.0°, and the sliding angle (SA) was 6.0°. Additionally, the modified wood showed a notable reduction in water uptake and moisture absorption, enhancing its dimensional stability. The superhydrophobic surface endowed the wood with excellent self-cleaning properties and robust resistance to pollution. Enhanced mechanical durability of superhydrophobic surface was observed under rigorous testing conditions, including sandpaper abrasion and tape peeling. Furthermore, the modification improved the thermal stability, compressive strength, and storage modulus of the wood. Collectively, these enhancements render this modification a potent methodology for the preservation and functional augmentation of historic architectural woodwork.