Open Access. Powered by Scholars. Published by Universities.®
- File Type
Articles 1 - 4 of 4
Full-Text Articles in Physics
Double Layer In Ionic Liquids: Overscreening Versus Crowding, Martin Z. Bazant, Brian D. Storey, Alexei A. Kornyshev
Double Layer In Ionic Liquids: Overscreening Versus Crowding, Martin Z. Bazant, Brian D. Storey, Alexei A. Kornyshev
Brian Storey
We develop a simple Landau-Ginzburg-type continuum theory of solvent-free ionic liquids and use it to predict the structure of the electrical double layer. The model captures overscreening from short-range correlations, dominant at small voltages, and steric constraints of finite ion sizes, which prevail at large voltages. Increasing the voltage gradually suppresses overscreening in favor of the crowding of counterions in a condensed inner layer near the electrode. This prediction, the ion profiles, and the capacitance-voltage dependence are consistent with recent computer simulations and experiments on room-temperature ionic liquids, using a correlation length of order the ion size.
Self-Assembly Of Helical Ribbons, Yevgeniya V. Zastavker, Neer Asherie, Aleksey Lomakin, Jayanti Pande, Joanne M. Donovan, Joel M. Schnur, George B. Benedek
Self-Assembly Of Helical Ribbons, Yevgeniya V. Zastavker, Neer Asherie, Aleksey Lomakin, Jayanti Pande, Joanne M. Donovan, Joel M. Schnur, George B. Benedek
Yevgeniya V. Zastavker
The self-assembly of helical ribbons is examined in a variety of multicomponent enantiomerically pure systems that contain a bile salt or a nonionic detergent, a phosphatidylcholine or a fatty acid, and a steroid analog of cholesterol. In almost all systems, two different pitch types of helical ribbons are observed: high pitch, with a pitch angle of 54 ± 2°, and low pitch, with a pitch angle of 11 ± 2°. Although the majority of these helices are right-handed, a small proportion of left-handed helices is observed. Additionally, a third type of helical ribbon, with a pitch angle in the range …
Tension-Induced Straightening Transition Of Self-Assembled Helical Ribbons, Yevgeniya V. Zastavker, Brice Smith, George B. Benedek
Tension-Induced Straightening Transition Of Self-Assembled Helical Ribbons, Yevgeniya V. Zastavker, Brice Smith, George B. Benedek
Yevgeniya V. Zastavker
Helical ribbons with pitch angles of either 11° or 54° self-assemble in a wide variety of quaternary surfactant-phospholipid/fatty acid-sterol-water systems. By elastically deforming these helices, we examined their response to uniaxial forces. Under sufficient tension, a low pitch helix reversibly separates into a straight domain with a pitch angle of 90° and a helical domain with a pitch angle of 16.5°. Using a newly developed continuum elastic free energy model, we have shown that this phenomenon can be understood as a first order mechanical phase transition.
Non-Linear Dynamic Intertwining Of Rods With Self-Contact, Christopher Lee, Sachin Goyal, Noel Perkins
Non-Linear Dynamic Intertwining Of Rods With Self-Contact, Christopher Lee, Sachin Goyal, Noel Perkins
Christopher Lee
Twisted marine cables on the sea floor can form highly contorted three-dimensional loops that resemble tangles. Such tangles or ‘hockles’ are topologically equivalent to the plectomenes that form in supercoiled DNA molecules. The dynamic evolution of these intertwined loops is studied herein using a computationalrod model that explicitly accounts for dynamicself-contact. Numerical solutions are presented for an illustrative example of a long rod subjected to increasing twist at one end. The solutions reveal the dynamicevolution of the rod from an initially straight state, through a buckled state in the approximate form of a helix, through the dynamic collapse of this …