Hydration structure and mobility of the water contained in poly(ethylene terephthalate).

We have studied the state of the water contained in poly(ethylene terephthalate) (PET), which consists of repeat units of OCC6H4COOCH2CH2O, in variously hydrated states. We first determined the hydration structure of the water therein not only from its OH stretching spectrum in a thinner sample but also from the hydration energy, the effect of the hydrogen bonding on the lengths of the donor and acceptor bonds, and the OH stretching frequencies of the water for the optimized 1:1 hydrate structures (quantum-chemically calculated). It has been found that the water bridges two ester C═O's in the manner of C═O···H-O-H···O═C therein and that about a 0.

Infrared and near-infrared study of the interaction of amide C=O with water in ideally inert medium.

Hydration property of amide C=O was investigated from the OH stretching fundamentals and the first combinations of the water in the hydrate, formed in hydrophobic solution of an N,N-dialkyl amide ((CH(3)CH(2))(2)NCO(CH(2))(10)CH(3)) in heptane. The property was also examined for ester C=O of an alkyl ester (CH(3)(CH(2))(8)COOCH(3)) for comparison. The hydrates of C=O.

Infrared spectroscopic study of the effect of electrostatic interaction on the molecular arrangement in the hydration shell around Li+ in a nafion membrane.

In the present paper we characterize the hydration shell around a Li ion, as -SO(3)(-)Li(+), from a series of infrared spectra of the hydrated Li salt in a sample of Nafion. The infrared spectrum significantly changes through prolonged dehydration under a controlled flow of drying gas, to a limiting dryness level. We found that the Nafion membrane contains a small population of the SO(3)(-)Li(+) group isolated in a hydrophobic matrix (denoted A) in addition to the main component of the clustered group (B).

Determination of the hydrate structure of an isolated alcoholic OH in hydrophobic medium by infrared and near-infrared spectroscopy.

This paper reports the structure of the hydrate complex of an isolated alcoholic OH, produced in a small amount in hydrophobic solution in heptane. The structure was determined from the changes, caused by hydration, in the infrared and near-infrared spectra of 2-nonanol in the solution. The changes were exhibited in the "difference" spectrum, in which the spectrum of the solution before hydration was subtracted from that after hydration.

Near-infrared spectroscopy as a useful tool for analysis in solution in common organic solvents.

In the present paper we report that near-infrared spectroscopy is a useful tool for analyzing solutes in solution in common organic solvents. This is because the near-infrared absorptions of the solvent are not so strong as to disturb the separation of the characteristic near-infrared bands, by subtraction, of the solute. To demonstrate this capability, we first showed that the near-infrared absorptions of heptane and toluene, each of which represents aliphatic or aromatic solvents, do not significantly affect the noise level of the difference spectrum, in which the near-infrared spectrum of a solute is to be separated by subtraction.

Characterization of infrared and near-infrared absorptions of free alcoholic OH groups in hydrocarbon.

We have demonstrated that the near-infrared and infrared absorptions in the 8000-3200 cm(-1) region of an OH group of 2-nonanol, 1-nonanol, etc., in n-heptane are excellently separated by subtraction without any serious interference down to very low concentrations at which OH groups are completely free. The separated sharp absorptions are assigned to the fundamental, combination, and overtone bands that are concerned with the OH stretching of free OH.

Infrared and near-infrared spectral evidence for water clustering in highly hydrated poly(methyl methacrylate).

First, we developed quantitative analytical methods of water in poly(methyl methacrylate) (PMMA) in various hydrated states by utilizing the first combination and OH stretching bands of water at about 5240 and 3630 cm-1, respectively. Next, we investigated how the state of water depended on its quantity or the mole ratio of water to the CO (denoted as the H2O/CO ratio), which only interacts with water in PMMA, mainly on the basis of the band feature of the OH stretching bands. Below the H2O/CO ratio of 0.

Near-infrared combination and overtone bands of the CH2 sequence in CH2X2, CH2XCHX2, and CH3(CH2)5CH3 and their characteristic frequency zones.

We characterized near-infrared spectra of the CH2 sequence in CH2X2 (X=halogen), CH2ClCHCl2, and CH3(CH2)5CH3. Each near-infrared absorption in the region from 3500 to 10,000 cm-1 is consistently assigned to one of the five different combination or overtone groups, in the order of increasing frequency, of the {[v(CH)]+[delta(CH)]} (A), {[v(CH)]+[2delta(CH)]} (B), [2v(CH)] (C), {[2v(CH)]+[delta(CH)]} (D), and [3v(CH)] (E) types, where v(CH) and delta(CH) denote the CH stretching and CH deformation normal modes, respectively. Each group has its own characteristic frequency zone.

Near-infrared combination and overtone bands of CH in CHX3, CHX(2)-CHX2, and CHX(2)-CX(2)-CHX2.

In the present report we studied spectral characteristics of the near-infrared combination and overtone bands of CH vibrations of a CH sequence. The near-infrared bands of the CH in CHX3 (X, halogen), which were interpreted in terms of the CH stretching and CH deformation fundamentals without any ambiguity, typically showed how the frequency and intensity of a combination or an overtone depend on the vibrational excited state. In the CH-C-CH of CHX2CX2CHX2, the vibrations of one CH are isolated from those of the other CH, and the combination and overtone bands were similarly interpreted as those of the CH, although each of the combination bands was split into two because of non-degeneracy of the CH deformation.

Contrast effect of hydrogen bonding on the acceptor and donor OH groups of intramolecularly hydrogen-bonded OH pairs in diols.

We studied the influence of hydrogen bonding on the fundamental and overtone bands of the OH-stretching vibration of each OH group in the intramolecularly hydrogen-bonded OH(I)::OH(II) pair in 1,2-, 1,3- and 1,4-diols. The hydrogen bonding between the two OH groups significantly increases in strength from the five-membered ring of a 1,2-diol to the seven-membered ring of a 1,4-diol. Although the hydrogen bonding does not affect the vibrational property of the OH(II) (or acceptor), it significantly influences the OH(I) (or donor).

Responsiveness of the first combination band of water to the state in organic and polymeric medium.

We studied the influence of intermolecular interactions on the first combination band between the OH-stretching and -deformation vibrations of the water that is dissolved in organic and polymeric materials. The water has two types. The first type occurs in the matrix in which water-interactive functional groups are densely distributed.