Dielectric spectroscopy, combined with

There is a constant challenge for improved techniques in order to make accurate predictions on the colloidal stability of various sytems. In this section we demonstrate how dielectric spectroscopy can be applied as a technique to follow the breakdown of water-in-oil emulsions and to monitor the sedimentation of particle suspensions. Dielectric spectroscopy, combined with statistical test design and evaluation, seems to be an appropriate technique for the study of these problems. However, one should continue to seek satisfactory theoretical models for the dielectric properties of inhomogeneous systems. 

The same information may be obtained from purely rotational far infrared spectroscopy (FIR) and depolarized Rayleigh spectra. Dielectric relaxation measurements are also used for the same goal, most successfully in combination with far-infrared data. The absorption coefficient of a periodic electric field... 

DSC is increasingly being applied to the study of epoxy resin cure in combination with other analytical methods such as nuclear magnetic resonance and Fourier transform infra-red spectroscopy, chromatographic methods, and dynamic mechanical or dielectric studies. It is probably as part of such combined investigations that DSC can be used most effectively in basic research, and in quality control and assessment. 

However, in an attempt to integrate the SFA and spectroscopic techniques, the use of silver for optical interferometry has been seen as a drawback due to the fact that it precluded sufficient excitation source intensity to illuminate the buried interface. In order to circumvent this problem Mukhopadhyay and co-workers in an experimental set-up where the SFA was combined with fluorescence correlation spectroscopy (FCS) used, instead of silver, multilayer dielectric coatings that allowed simultaneous interferometry and fluorescence measurements in different regions of the optical spectrum [75]. Using this set-up they succeeded in measuring diffusion in molecularly thin films with singlemolecule sensitivity. 

Fordedal and Sjoblom used dielectric spectroscopy to study several real erode oil emulsions and model systems stabilized with either separated asphaltenes and resins from crude oil or by commercial surfactants (55). Emulsions could be stabilized by the asphaltene fraction alone, but not by the resin fraction alone. A study of a combination of mixtures shows an important interaction between emulsifying components. F0rdedal et al. used dielectric spectroscopy to study model emulsions stabilized by asphaltenes extracted from crude oils (56). Analysis showed that the choice of organic solvent and the amount of asphaltenes, as well as the interaction between these variables, were the most significant parameters for determining the stability of the emulsions. 

Heterogenous dielectric systems exhibit some special properties, among which most notable is interfacial polarization caused by hindered charge movement at the interfaces. This effect makes dielectric spectroscopy (AC and DC methods), in combination with other methods of structure determination, a usefol tool in studying the following phenomena in composite materials ... 

Abstract. The simultaneous combination of scattering techniques, probing structure, with relaxation techniques, detecting modifications of the amorphous phase dynamics, can be helpful in order to obtain complementary information about crystallization processes in polar polymers. The objective of this contribution is to review the improvements in the combination of real time (wide and small angle) X-ray scattering and dielectric spectroscopy aiming at a better understanding of polymer crystallization. 

Samouillan et al. (2011) studied the dielectric properties of elastin at different degrees of hydration and specifically at the limit of freezable water apparition. The quantification of freezable water was performed by DSC. Two dielectric techniques were used to explore the dipolar relaxations of hydrated elastin dynamic dielectric spectroscopy (DDS), performed isothermally with the frequency varying from 10 to 3 x 10 Hz, and the TSDC technique, an isochronal spectrometry running at variable temperature, analogous to a low-frequency spectroscopy (10 to 10 Hz). A complex relaxation map was evidenced by the two techniques. Assignments for the different processes can be proposed by the combination of DDS and TSDC experiments and the determination of the activation parameters of the relaxation times. As already observed for globular proteins, the concept of solvent-slaved protein motions was checked for the fibrillar hydrated elastin (Samouillan et al. 2011). 

The systems studied served as model mixtures for dielectric coatings for printed circuits. The curing behavior was monitored by FTIR spectroscopy, also in combination with photoacoustic spectroscopy. These methods provided information on the... 

Whereas most of the older literature presents specific ion effects on a macroscopic level, recent investigations highlight the specific molecular distributions of ions and their specific hydration in aqueous phases or near interfaces [13, 17]. Most useful are X-ray and neutron scattering experiments [18], terahertz and IR spectroscopy [19], dielectric relaxation spectroscopy [20], and NMR [21] combined with computer... 

Abstract The physical principles and basic experimental techniques of impedance spectroscopy, i. e. static or frequency dependent dielectric permittivity measurements of sorbent/sorbate systems are given. These measurements can be used to characterize the state of a sorbent material in industrial adsorption processes. Combined with either manometric or gravimetric measurements of adsorption equilibria leading to calibration curves, permittivity measurements also allow fairly simple and quick measurements of gas adsorption equilibria. Kinetic processes and catalytic reactions inside a sorbent/sorbate system also can be observed. Pros and cons of dielectric measurements are discussed. List of Symbols. References. 

Further examinations showed the temperature dependence of the structure by employing combined/hyphenated temperature-dependent measurements. By combination of T-WAXS, T-SAXS [133], temperature-dependent F solid state NMR, rheology (complex viscosity as function of temperature/frequency) [134] as well as dielectric spectroscopy [135] proved the probability of the model and the change of the structure with temperature. 

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