Investigation of the molecular description of small molecules in void spaces of wood using dielectric measurements

In this study, dielectric measurements were performed on wood from an evergreen conifer tree, Cryptomeria japonica, impregnated with various aqueous solutions to investigate the molecular description of water and solute molecules in the void spaces of the wood. While the Kohlrausch–Williams–Watts-type asymmetric relaxation process reflecting the motion of the free water and solute molecules was observed in the bulk state, the Cole–Cole-type symmetric relaxation process was observed when the wood was impregnated with the aqueous solution. This symmetric relaxation process observed in the wood impregnated with the aqueous solution can be interpreted using a cooperative domain with a heterogeneous size distribution that describe the dielectric properties of bulk aqueous solutions. The relationship between the molecular structure of the solute and the cooperative domain formed by water and solute molecules that remain inside the voids of wood is discussed.