Amount Of Mobile Ions Research Articles

Temperature, humidity, and dimension dependence of the bending motion of ionomer-based polymer actuators

This paper focuses on the effects of temperature, humidity, and dimensions on the displacement of ionomer-based polymer actuators. The amount of displacement and velocities of the actuation strongly increased with increasing humidity and temperature. We attributed this behavior to a change in the Young's modulus (the stiffness) and ion conductivity based on water uptake. To evaluate the dependence of the velocity of the displacement on humidity and temperature, we examined three velocities (i.e. the initial, bending, and backtracking velocities). The observed increase in the bending velocity at higher relative humidity (RH) levels arises from an increase in the water uptake, which enhances ion conductivity and decreases the film stiffness. The ratio of the bending velocity to the backtracking velocity at higher RH decreased because of a drastic increase of the backtracking velocity at higher RH. This result would be explained by an increase in the ion conductivity accompanying a decrease in the stiffness. Furthermore, we compared the difference in the amount of displacement of the actuator using actuators of two widths (2 and 10 mm) at 30, 60, and 90% RH and at 25 °C. The difference in the width of the actuator did not completely affect the displacement. These results are reasonably explained by considering the amount of mobile ions per unit volume of the films of the actuators. Copyright © 2016 John Wiley & Sons, Ltd.

Ion Density Analysis of Single-Stranded DNA in Liquid Crystal

With the widespread use of liquid crystals (LCs) in liquid crystal displays, we have looked into the application of liquid crystals in biotechnology. The purpose of the study described here is to investigate the physical properties of DNA using LCs. Synthetic oligonucleotide molecules were dispersed in MLC6884, the sample injected into antiparallel cells, and the amount of mobile ions was measured. The LC cell doped with oligonucleotide molecules showed a sequence-dependent, specific correlation between oligonucleotide concentration and the amount of mobile ions in the LC cells. In the framework of the Stokes model and polyacrylamide gel electrophoresis (PAGE) analysis, we speculate that this result arises from the difference in ion mobility, which is caused by the shape of the oligonucleotide molecule in the LC.

Adsorption of fluids in slitlike pores containing a small amount of mobile ions

We apply density functional theory to investigate changes in the phase behavior of a fluid caused by the presence of mobile ions inside the pore. The approach has been based on the fundamental measure density functional theory and on the theory of nonuniform electrolytes developed recently by O. Pizio, A. Patrykiejew, S. Sokołowski [J. Chem. Phys. 121 (2005) 11,957]. We have evaluated capillary condensation phase diagrams for pores of different widths and for different concentrations of confined ions. The calculations have demonstrated that the presence of ions leads to lowering the critical temperature and to an increase of the value of the chemical potential at the capillary condensation point.