Penta­decyl­ammonium methyl sulfate

In the crystal of the title compound, C15H34N+·CH3SO4 −, the cations and anions are joined together via strong N—H⋯O hydrogen bonds into layers parallel to (001)

n-Tridecyl­amine chloride monohydrate

In the title compound, C13H30N+·Cl−·H2O, the C13H27 alkyl chain is in an all-trans conformation. In the crystal, inter­molecular N—H⋯Cl, N—H⋯O and O—H⋯Cl hydrogen bonds connect the components into layers parallel to (010), with the alkyl chains oriented approximately perpendicular to these layers

n-Dodecyl­ammonium bromide monohydrate

In the title compound, C12H28N+·Br−·H2O, the ionic pairs formed by n-dodecyl­ammonium cations and bromide anions are arranged into thick layers; these layers are linked in a nearly perpendicular fashion [the angle between the layers is 85.84 (5)°] by hydrogen-bonding inter­actions involving the water mol­ecules. The methyl­ene part of the alkyl chain in the cation adopts an all-trans conformation. In the crystal structure, mol­ecules are linked by inter­molecular N—H⋯Br, O—H⋯Br and N—H⋯O hydrogen bonds

Aggregation behavior of fluorooctanols in hydrocarbon solvents

金沢大学理工研究域物質化学系The association behaviors of three 1-octanols (1-octanol: C8OH; 1,1,2,2-tetrahydrotridecafluorooctanol TFC8OH; and 1,1-dihydropentadecafluorooctanol: DFC8OH) in two hydrocarbon solvents (n-hexane and benzene) were examined by vibration spectroscopy from 288.15 to 318.15 K. From the analysis of results with a mass action model, it was found that dimers and tetramers of 1-octanols coexisted with monomers in the n-hexane solution. These aggregates were formed by hydrogen bonding between the OH groups of 1-octanols. In the n-hexane solutions, an increase in the fluorination number of the 1-octanol molecule enhanced the intermolecular hydrogen bonding between the OH groups, but reduced the amounts of polymeric species. Conversely, in the benzene solution, the NIR experiment suggested that the OH groups of 1-octanols did not interact with other OH groups, but with the benzene molecules instead. It was found from 19F NMR chemical shift measurements that the fluorooctanols in the benzene solution aggregated by interaction between the fluorocarbon chains instead of by hydrogen bonding

Line tension and its influence on droplets and particles at surfaces

In this review we examine the influence of the line tension τ on droplets and particles at surfaces. The line tension influences the nucleation behavior and contact angle of liquid droplets at both liquid and solid surfaces and alters the attachment energetics of solid particles to liquid surfaces. Many factors, occurring over a wide range of length scales, contribute to the line tension. On atomic scales, atomic rearrangements and reorientations of submolecular components give rise to an atomic line tension contribution τatom (∼1 nN), which depends on the similarity/dissimilarity of the droplet/particle surface composition compared with the surface upon which it resides. At nanometer length scales, an integration over the van der Waals interfacial potential gives rise to a mesoscale contribution |τvdW| ∼ 1–100 pN while, at millimeter length scales, the gravitational potential provides a gravitational contribution τgrav ∼ +1–10 μN. τgrav is always positive, whereas, τvdW can have either sign. Near wetting, for very small contact angle droplets, a negative line tension may give rise to a contact line instability. We examine these and other issues in this review

Cryogenic neutron detector comprising an InSb semiconductor detector and a supercritical helium-3 gas converter

We evaluated the neutron-detection characteristics of a proposed cryogenicneutrondetector comprising an InSbsemiconductordetector and a helium-3 gas converter. The neutrondetector was operated at 4.2 K with helium-3 gas filling up to 1.5 atm, at which the density of the helium-3 nucleus corresponds to that at 160 atm at room temperature. The secondary particles generated by the [3]He(n, p)Treaction were successfully detected by the InSbdetector with a time response of ∼80 ns at all tested gas pressures