Research Progress on Advanced Characterization Methods for Hydration Interfaces in Wood Micro- and Nanochannels

Wood–water interactions are a central focus in wood science, profoundly influencing wood’s physical, chemical, and mechanical properties. These interactions play a decisive role in wood processing, application, and durability. With scientific advancements, research has progressed from the macroscopic scale to fine microscopic levels, focusing on hydration within wood’s micro/nano channels. However, traditional methods are limited by wood’s complex hierarchical structure, making it difficult to accurately analyze water molecule behavior and the influence of interfacial microstructures in confined spaces. This paper reviews recent applications of advanced characterization methods in studying hydration interactions within wood’s micro/nano channels. It details the basic principles of methods such as nuclear magnetic resonance, Fourier transform infrared spectroscopy, and differential scanning calorimetry, along with their specific applications in characterizing wood–water interactions, moisture states, and cell-scale moisture distribution. This review offers new perspectives for understanding hydration in wood micro/nano channels. It reveals that interfacial confinement fundamentally alters the hydrogen bonding network and dynamic characteristics of water molecules, which is crucial for designing next-generation wood-based materials.