Nuclear magnetic relaxation of water in hydrogels

Spatially resolved solvent interaction with glassy HPMC polymers studied by magnetic resonance microscopy

“…Most probably also the other contribution to the proton solvent T 2 within the gel of HPMC matrix should be taken into consideration i.e. a chemical exchange between water protons and hydrogen of hydroxyl groups of side chains of the monomeric units of polymer, but also between water protons and the hydroxyl group of the alkaline solvent [34][35][36][37]. However, our measurements were not able to distinguish the contributions from the particular sources of the relaxation to the measured T 2 values.…”

Water Dynamics in Bolaamphiphile Hydrogels Investigated by 1H NMR Relaxometry and Diffusometry

“…There is only a slight decrease of the T 2m values observable for the hydrogel with 30 mg/mL PC-C32-PC compared to pure water. As shown by Roorda et al for poly(hydroxyethyl methacrylate) (pHEMA) hydrogels, 27 the observed small effect on the relaxation of the water protons can be fully explained as a concentration effect. These authors determined the relaxation rate enhancement factors (REF)…”

Effect of microwave irradiation on the hydroxypropyl methylcellulose powder and its hydrogel studied by Magnetic Resonance Imaging

“…Therefore, in order to explain this fact we have to assume that in addition to a fast exchange between the free and bound state of water also a rapid proton exchange between water protons and the hydrogen of the hydroxyl groups of the side chains of the monomeric units of HPMC polymer is a major transverse relaxation mechanism in the studied hydrogels. The situation is found in other polymer systems, also for cellulose gels (Barbieri et al, 1998;Hills, Wright, & Belton, 1990;Lewis & Derbyshire, 1987;Nystrom, Moseley, Brown, & Roots, 1981;Roorda, De Bleyser, Junginger, & Leyte, 1990). In such a case the observed T 2 value is expressed by Eq.…”