Simon Schrödle

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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(More)
Calcium fluoride is a slightly soluble compound commonly extracted from ores via flotation at elevated pH, where surfactant molecules bind with hydroxylated surface sites. The addition of F-(aq) suppresses surfactant adsorption by replacing these sites. In this paper, we look at the effects of aqueous Cl-, Br-, F-, and SO4(2-) on the water structure at the(More)
Dielectric spectra were measured for eight, mostly imidazolium-based, room temperature ionic liquids (RTILs) over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) and temperatures (5 < or = theta/degrees C < or = 65). Detailed analysis of the spectra shows that the dominant low frequency process centred at ca. 0.06 to 10 GHz (depending on the salt(More)
Dielectric spectra from 200 MHz up to 3 THz were determined to study the fast dynamics of dilute water+1,4-dioxane. epsilon(nu) could be fitted by a collision induced oscillator at high frequencies plus two Debye relaxations in the microwave region. Isotope substitution was used to assign water and dioxane modes. The presence of the cooperative(More)
Vibrational sum-frequency spectroscopy is a powerful tool for the study of interfaces, but its application has hitherto mainly been limited to static structure. This contribution demonstrates how the considerably improved stability of state-of-the-art lasers and parametric generators can be exploited to study the evolution of interfacial structure(More)
Precise complex permittivity spectra over the frequency range 0.15 GHz </= nu </= 89 GHz are reported for monodisperse (EGn, 1 </= n </= 6) and polydisperse (PEG174, PEG300, PEG400) oligo(ethylene glycol)s at 25 degrees C. Up to about 20 GHz, the relaxation behavior of all samples can be reasonably described with empirical functions that reflect a broad and(More)
Self-assembly of surface-active agents at solid–liquid interfaces is critical for many processes in nature and technology, including the stability of suspension, detergency, wetting and mineral separation. [1] Historically, a detailed understanding of nano-meter-scale layers has emerged. However, surprisingly little is known about their dynamics—the key to(More)
Ion association in aqueous solutions of scandium sulfate has been investigated at 25 degrees C and at concentrations from 0.01 to 0.8 M by broadband dielectric spectroscopy over the frequency range 0.2 <or= nu/GHz <or= 89. Detailed analysis of the spectra reveals the presence of both inner- and outer-sphere 1:1 [ScSO 4] (+)(aq) complexes, similar to(More)
The adsorption, desorption, and equilibrium monomer exchange processes of sodium dodecanoate at the fluorite(CaF 2)-water interface have been studied. For the first time, we use in situ vibrational sum-frequency spectroscopy (VSFS) to gain insights into the mechanism and kinetics of monolayer self-assembly at the mineral-water interface. By exploiting the(More)
A dielectric relaxation study of binary mixtures of nonionic surfactant C12E5 + water has been made as a function of temperature in the isotropic micellar, lamellar, and hexagonal regions of the phase diagram. Two dielectric dispersion steps were found and could be assigned to the intermolecular cooperative dynamics of water at the micellar interface and in(More)