¹H‐NMR studies on water in methacrylate hydrogels. II

Abstract

SYNOPSISProperties of water in the wet membranes of a random copolymer of methyl methacrylate and methoxy poly (ethylene glycol) -monomethacrylate P ( MMA-co-Ml00G) and of a graft copolymer of vinyl chloride and methoxy poly (ethylene glycol) -monomethacrylate P (VCg-M100G) membranes were studied by proton NMR spectroscopy. Both polymers contain flexible polyoxyethylene side chains. Temperature and frequency dependences of relaxation times, changes of signal intensity of water protons on freezing and thawing, and saturation transfer were measured for both copolymers. These experimental results revealed that most of the bound water in these copolymers does not exist in a rigid state as suggested for the other hydrogels. The introduction of flexible hydrophilic side chains resulted in high mobility of the water molecules bound to the side chains (the apparent correlation time 7, -lo-'' s ) . For the graft copolymer P ( VC-g-M100G) , hydrophilic polyoxyethylene side chains are contiguous to each other. Because of the interaction between the side chains, the mobility became more complex than that for the random copolymer P ( MMA-co-M100G) . The difference in the mode of mobility of water on the membrane surface may be related to the difference of the membrane characteristics of these copolymers.

Mechanism for selective binding of aromatic compounds on oxygen-rich graphene nanosheets based on molecule size/polarity matching

“…S4 document that the broad signal exhibits very fast T 1 relaxation on the time scale of 0.05 ms, indicating large-amplitude dynamics with rates near the T 1 minimum, on the order of pulse field strength (i.e., |B 1 | = 3 × 10 5 /s) (40), corresponding to rotation correlation times near 3 s. The rotation correlation time of water bound on GO is six orders of magnitude longer than that of bulk liquid water (41) and is in a similar order to that reported for structural water in proteins (42) and hydrogels (43). The result indicates the strong and irreversible interactions of the water molecules with the GO surface.…”

Effect of Sodium Chloride on Hydration Structures of PMEA and P(MPC-r-BMA)

“…Water molecules located at the interfaces between medical polymers and biological systems play important roles for their biocompatibility. − Water molecules hydrating to synthetic polymers as well as biopolymers have been characterized and classified by thermal analysis. , Three different types of hydrating water of nonfreezing water (tightly bound water), freezing bound water (loosely bound water or intermediate water), and freezing water (scarcely bound water or free water) have been found in many biorelated molecules by the analysis. , The detailed hydration structures of each classified water molecule to a polymer chain accompanied by noncovalent interactions have recently been explored at the functional group level using molecular spectroscopic techniques such as vibrational spectroscopy , and nuclear magnetic resonance (NMR) spectroscopy. − …”

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

“…This means that water molecules within the HPMC gel are characterized by a single relaxation time T 2 and diffusion constant D. Therefore, it is reasonable to assume that the water molecules of different types: free and bound are in fast diffusive exchange with respect to the chemical shift or in the intermediate exchange regime with respect to the spin-spin relaxation time (Ganapathy, Rajamohanan, Badiger, Mandhare, & Mashelkar, 2000;Quinn, McBrierty, & Wilson, 1990;Smyth, Quinn, & McBrierty, 1988;Sung, Gregonis, John, & Andrade, 1981;Yamada-Nosaka, Ishikiriyama, & Todoki, 1990).…”