We have measured the dielectric relaxation of the glass-former 1-propanol for temperatures between 65 and 350 K in the frequency range 10−2 to 2⋅1010 Hz and the photon correlation spectro-scopy decays near Tg. Attributing the strong Debye-type process of 1-propanol to distinct -OH group effects leaves two faster processes related to the structural relaxation which can be identified as α-relaxation and Johari–Goldstein type β-relaxation characteristic of nonhydrogen-bonding supercooled liquids. From the temperature dependent relaxation times τ(T) regarding the three distinct loss peaks, we can specify an α-β-bifurcation temperature Tβ, which coincides with characteristic qualitative changes in the τ(T) behavior, as also observed for ortho-terphenyl and other glass-forming liquids. This assignment is confirmed by the correla-tion times derived from incoherent quasielastic light-scattering data obtained from the simultaneously measured photon-correlation spectroscopy.

Dynamics of glass-forming liquids. III. Comparing the dielectric α- and β-relaxation of 1-propanol and o-terphenyl

A series of highly soluble and fluorescent, at core tetraaryloxy-substituted and in imide positions hydrogen atom containing perylene bisimide (PBI) dyes 1a−e with varying peripheral side chains have been synthesized and thoroughly characterized. The self-assembly of these PBIs has been studied in detail by UV/vis, linear dichroism (LD) and circular dichroism (CD) spectroscopy, and scanning probe microscopy (AFM, STM). These studies revealed that the present PBIs self-assemble into extended double string cables, which consist of two hydrogen-bonded supramolecular polymeric chains of densely packed and strongly excitonically coupled PBI chromophores, providing highly fluorescent J-aggregates. The aggregation strength (“melting” temperature) and the fluorescence properties of these J-aggregates are dependent on the number and chain length of the peripheral alkoxy substituents, thus revealing a structure−property relationship. In contrast to previously reported assemblies of PBIs, for which the aggregation p...

Fluorescent J-Aggregates of Core-Substituted Perylene Bisimides: Studies on Structure−Property Relationship, Nucleation−Elongation Mechanism, and Sergeants-and-Soldiers Principle

A review of the current state of understanding of dielectric mixture properties, and approaches to use numerical calculations for their modeling are presented. It is shown that interfacial polarization can yield different non-Debye dielectric responses depending on the properties of the constituents, their concentrations and geometrical arrangements. Future challenges on the subject are also discussed.

Dielectric mixtures: electrical properties and modeling

New Hybrid Organic−Inorganic Solids with Helical Morphology via H-Bond Mediated Sol−Gel Hydrolysis of Silyl Derivatives of Chiral (R,R)- or (S,S)-Diureidocyclohexane

Chiral recognition in organogels occurs in the coassembly of the chiral gelator 1 with the chiral guest molecule 2. The diastereomeric aggregates formed from (R,R)-2 with (R,R)-1 or (S,S)-1 were found to be truly different in structure and strength. Cooperativity makes a major contribution to the chiral recognition in this system.

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Chiral Recognition in Bis-Urea-Based Aggregates and Organogels through Cooperative Interactions.

Structure of hydrogen-bonded sym-dialkylureas in nonpolar organic media

A dielectric relaxation study of some mixtures of mono and dihydric alcohols

The dielectric relaxation spectrum is measured at 20°C at frequencies up to 72 GHz for the following alcohols and their aqueous mixtures over the whole mixture range: 1,2-ethanediol; 1,2- and 1,3-propanediol; 1,2-, 1,3-, 1,4- and 2,3-butanediol; for comparison moreover: ethanol; diethyleneglycol and 1,2,3-propanediol. It is found possible to analyze the spectra into discrete spectral components according to one and the same scheme in all cases. Three mixture ranges can be distinguished on the volume fraction scale, the parameters of the intermediate and, particularly, the water rich region being rather insensitive to the nature of the alcoholic component.

A Dielectric Relaxation Study of Some Liquid Dihydric Alcohols and Their Mixtures with Water

Excess molar volumes, V m E , for binary mixtures of eight aliphatic amino alcohols (2-aminoethanol 3-amino-1-propanol, 4-amino-1-butanol, 5-amino-1-pentanol, 2-amino-1-propanol, 1-amino-2-propanol, 2-amino-2-methyl-1-propanol, and 2-amino-1-butanol) with 1,4-dioxane have been determined from the density measurements at 293.1 K by means of a vibrating tube densimeter

M. Stockhausen

Papers

Structure of hydrogen-bonded sym-dialkylureas in nonpolar organic media

A dielectric relaxation study of some mixtures of mono and dihydric alcohols

A Dielectric Relaxation Study of Some Liquid Dihydric Alcohols and Their Mixtures with Water

Excess Molar Volumes of Binary Mixtures of Amino Alcohols with 1,4-Dioxane

Static and dynamic dielectric properties of aminoalcohols in their pure liquid state and in mixtures with dioxane