Properties of Water in Macromolecular Gels. V. Anomalous Temperature Dependence of the Nuclear Magnetic Resonance Line-width of Water in Macromolecular Gels

Abstract

The line-width of the nuclear magnetic resonance (NMR) signal gets narrow, in general, with an increase in the temperature. In contrast, the NMR line-width of the water proton in agarose gels was found to increase with an increase in the temperature up to about 30°C. As for the other polysaccharide gels, such as curdlan-type polysaccharide, and κ-and λ-carrageenan gels, the NMR line-width of water increases with an increase in the temperature. The anomalous temperature dependence of the line-width was most marked in agarose gels than in other polysaccharide gels. The close relationship between the gel network, which consists of small cavities (microspace) of the micelle, and the magnitude of the anomality was revealed, this anomalous effect was named the “Micro-Space Effect.”

Multiexponential proton relaxation processes of compartmentalized water in gels

“…Proton relaxation times of compartmentalized water have been determined in tissues (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), gels (22)(23)(24)(25), food materials ( 2 6 ) , and plants (27). In general, a monoexponential relaxation process of water in a closed compartment indicates fast exchange between free water and hydration water according to and h relate to free and hydration water.…”

Distribution processes of inorganic solutes in gel chromatography

“…The overall thermodynamic distribution coefficient Kd,xZ of the ion Xn~, which is the counterion in eq 7, when eluted with the solution of the salt consisting of W?+ and 71 is given by the following equation. log Kd,F = lQg -¿ (2 µ 0 + f ¿Mw°-%Z°J (8) Hence, from eq 7 and 8, we obtain log Kd,¡P = log , + Fx(Ka) + kx kl"-i3 \2 µ* ~ µ + µ ~2 µ ) (11) Equation 9 holds not only for a given single ion, Xn", but rather for all ions of the same valency, n-.…”

“…However, it seems likely that the properties of the solvent in gel differ from those of bulk of the solvent by the possible interaction between the solvent molecule and the gel matrix. For instance, water molecules in macromolecular gels generally exhibit physical properties distinct from those of ordinary free water by the interaction with hydrophilic groups or hydro- phobic part of the gel matrix (9)(10)(11)(12). Consequently, it is reasonable to assume that the concentration of the solute in the available part of the gel phase, Cp, is not necessarily identical with that in the external solution phase, C0.…”