9 Dielectric relaxation in solutions

Buchner, Richard; Barthel, J.

doi:10.1039/b101629f

Cited by 65 publications

(84 citation statements)

References 295 publications

(275 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Due to its sensitivity to all kinds of dipole moment fluctuations in the pico-and nanosecond time scale, [2] broadband dielectric (relaxation) spectroscopy (DRS), which involves the measurement of the complex dielectric permittivity of a sample [Equation (1)] e Ã(n) e'(n) À ie''(n)…”

Section: Introductionmentioning

confidence: 99%

Micelle and Solvent Relaxation in Aqueous Sodium Dodecylsulfate Solutions

et al. 2003

Self Cite

View full text Add to dashboard Cite

Dielectric spectra have been measured for aqueous sodium dodecylsulfate (SDS) solutions up to 0.1 mol L-1 at 25 degrees C over the frequency range 0.005 < or = nu GHz-1 < or = 89. The spectra exhibit two relaxation processes at approximately 0.03 GHz and 0.2 GHz associated with the presence of micelles in addition to the dominant solvent relaxation process at approximately 18 GHz and a small contribution at approximately 1.8 GHz due to H2O molecules hydrating the micelles. Detailed analysis reveals that the micelles bind 20 water molecules per SDS unit, but not as strongly as trimethylalkylammonium halide surfactants do. The relaxation times and amplitudes of both micelle relaxation processes can be simultaneously analysed with the theory of Grosse, yielding the effective volume of a SDS unit in the micelle and the lateral diffusion coefficient of the bound counterions. The findings of this investigation fully corroborate recent molecular dynamics simulations on structure and dynamics of SDS micelles.

show abstract

Section: Introductionmentioning

confidence: 99%

Micelle and Solvent Relaxation in Aqueous Sodium Dodecylsulfate Solutions

et al. 2003

Self Cite

View full text Add to dashboard Cite

show abstract

“…DRS measures the complex electric permittivity of a sample in response to an applied electromagnetic field in the microwave region (0.01 Շ ν/GHz Շ 100), as a function of the frequency of that field, ν. The use of DRS for quantifying ion-pairing equilibria is discussed at length elsewhere [13,15,16]. A key feature of DRS is that it detects species possessing a permanent dipole moment, µ. DRS is therefore able to discriminate between ion-pairs (which are dipoles) and free ions (for which µ is generally zero).…”

Section: Measurement Of Equilibrium Constantsmentioning

confidence: 99%

“…The most broadly applicable are undoubtedly the relaxation methods. Of these, dielectric relaxation spectroscopy (DRS) is probably the most useful [13,15,16]. DRS measures the complex electric permittivity of a sample in response to an applied electromagnetic field in the microwave region (0.01 Շ ν/GHz Շ 100), as a function of the frequency of that field, ν.…”

Section: Measurement Of Equilibrium Constantsmentioning

confidence: 99%

See 1 more Smart Citation

When spectroscopy fails: The measurement of ion pairing

Hefter

2006

Pure and Applied Chemistry

115

View full text Add to dashboard Cite

Spectroscopic techniques such as UV/vis, NMR, and Raman are powerful tools for the investigation of chemical speciation in solution. However, it is not widely recognized that such techniques do not always provide reliable information about ion association equilibria. Specifically, spectroscopic measurements do not in general produce thermodynamically meaningful association constants for non-contact ion pairs, where the ions are separated by one or more solvent molecules. Such systems can only be properly quantified by techniques such as dielectric or ultrasonic relaxation, which can detect all ion-pair types (or equilibria), or by traditional thermodynamic methods, which detect the overall level of association. Various types of quantitative data are presented for metal ion/sulfate systems in aqueous solution that demonstrate the inadequacy of the major spectroscopic techniques for the investigation of systems that involve solvent-separated ion pairs. The implications for ion association equilibria in general are briefly discussed.

show abstract

“…The measurable quantities in DRS as a function of the frequency of the applied alternative field are dielectric storage ε′, dielectric loss ε″, impedance Z, and the dynamic conductivity G(ω), where ω is the frequency of the applied alternating field. The permittivity can be expressed as follows 18 :…”

Section: Methodsmentioning

confidence: 99%

Characterization of DNA degradation using direct current conductivity and dynamic dielectric relaxation techniques

Sheu¹,

Sheu

2006

AAPS PharmSciTech

View full text Add to dashboard Cite

The purpose of this study was to evaluate DNA degradation upon thermal heating using dielectric relaxation and direct current (DC) conductivity methods. Herring sperm DNA, human growth hormone (HgH) plasmid DNA, and secreted alkaline phosphatase (SEAP) plasmid DNA were used as the examples. DNA was heated at 80°C for 1 hour. The dielectric relaxation spectra as a function of the applied field frequency were measured for HgH DNA at 0.5 hours and at 1 hour. The frequency range covered was from 10 kHz to 100 kHz. The DC conductivity measurements were made for all 3 kinds of DNA at 4 time points: 0 hours, 0.5 hours, 0.75 hours, and 1 hour. At each time point the DC conductivity was measured for each sample as a function of concentration via water dilution. The results show that the dielectric relaxation method is less sensitive in characterizing heat-driven DNA degradation. Conversely, DC conductivity is very sensitive. The semiquantitative dependence of the conductivity upon heating suggests that DNA degradation involves more than plasmid DNA nicking. Double strand and single strand breaks may also occur. In addition, herring sperm DNA, HgH DNA, and SEAP DNA, though similar in their DC conductivity functional forms upon dilution, exhibit significant differences in their responses to sustained heating.

show abstract

9 Dielectric relaxation in solutions

Cited by 65 publications

References 295 publications

Micelle and Solvent Relaxation in Aqueous Sodium Dodecylsulfate Solutions

Micelle and Solvent Relaxation in Aqueous Sodium Dodecylsulfate Solutions

When spectroscopy fails: The measurement of ion pairing

Characterization of DNA degradation using direct current conductivity and dynamic dielectric relaxation techniques

Contact Info

Product

Resources

About