The microscopic states, hydrogen-bonding configurations, and dielectric response characteristics of water molecules within porous media are central to water chemistry, geophysics, and moisture-sorption kinetics. When water molecules enter narrow aerogel nanopores, hydrophilic interactions between liquid molecules and surface polar groups disrupt and restructure the hydrogen-bonding network of bulk liquid water. Analyzing hydrogen-bonding restructuring and dielectric relaxation frequency shifts of water in porous media clarifies the electromagnetic response of confined water.

In macroscopic bulk water, molecules form a three-dimensional network via dynamically breaking and reforming hydrogen bonds, exhibiting characteristic dielectric relaxation frequencies. However, when water adsorbs onto aerogel nanopore walls, surface hydrophilic groups act as binding sites, locking adjacent water molecules into fixed orientations to form bound interfacial water layers. These layers exhibit distorted hydrogen bond lengths and angles, yielding dipole moments distinct from bulk water.

This hydrogen bond restructuring alters rotational freedom under alternating electric fields. In dielectric relaxation spectra, confined water relaxation times lengthen, shifting characteristic frequencies toward lower values. This frequency shift reflects interfacial interaction strengths and reveals the micro-physics governing dielectric property evolution in moist porous media.