scholarly journals Effects of passive phospholipid flip-flop and asymmetric external fields on bilayer phase equilibria

2018 ◽  
Author(s):  
J. J. Williamson ◽  
P. D. Olmsted
Keyword(s):  
Mechanical Properties ◽  
Phase Equilibria ◽  
Phase Behaviour ◽  
Domain Formation ◽  
External Fields ◽  
Protein Activity ◽  
Bilayer Membranes ◽  
Flip Flop ◽  
Substrate Interaction ◽  
Asymmetric Equilibrium

AbstractCompositional asymmetry between the leaflets of bilayer membranes is known to couple strongly to their phase behaviour, in addition to having important effects on, e.g., mechanical properties and protein activity. We address how phase behaviour is affected by passive phospholipid flip-flop, such that the compositional asymmetry is not fixed. We predict transitions from “pre flip-flop” behaviour to a restricted set of phase equilibria that can persist in the presence of passive flip-flop. Surprisingly, such states are not necessarily symmetric. We further account for external symmetry-breaking, such as a preferential substrate interaction, and show how this can stabilise strongly asymmetric equilibrium states. Our theory explains several experimental observations of flip-flop mediated changes in phase behaviour, and shows how domain formation and compositional asymmetry can be controlled in concert, by manipulating passive flip-flop rates and applying external fields.

Contribution of Electrostriction in Polyurethane/Polyaniline Blends

2014 ◽  
Vol 1025-1026 ◽  
pp. 697-702
Author(s):  
Darika Jaaoh ◽  
Chatchai Putson ◽  
Nantakan Muensit
Keyword(s):  
Mechanical Properties ◽  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Polymer Blend ◽  
Hard Segment ◽  
Filler Content ◽  
Domain Formation ◽  
Space Charges ◽  
Electrostrictive Polymer

In this work, we present a series of electrostrictive polymer blend that can potentially be used as actuators for a variety of applications. This polymer blend combines an electrostrictive polyurethane with a conductivity polyaniline polymer. The effect of filler content has been investigated. The structures of the blends, the electrical and mechanical properties which affect electrostrictive behavior were studied. The results showed that both dielectric constant and glass transition temperature of the blends increase with increasing polyaniline contents. Moreover, it was noted that space charges distribution and hard-segment domain formation significantly related with electrostrictive coefficient of polymer blend. Therefore, electrostriction behavior in the polymer blends has been demonstrated, and optimal microstructure for electrostriction enhancement has been identified.

Critical lines and phase equilibria in binary van der Waals mixtures

1980 ◽  
Vol 298 (1442) ◽  
pp. 495-540 ◽  
Keyword(s):  
Phase Equilibria ◽  
Binary Mixtures ◽  
Critical Points ◽  
Van Der Waals ◽  
Coexistence Curve ◽  
Phase Behaviour ◽  
Maximum Temperature ◽  
Phase System ◽  
Two Phase ◽  
Critical Solution Temperatures

The study of phase equilibria is historically one of the most important sources of information about the nature of intermolecular forces in non-electrolyte liquids and their mixtures. Many of the main features of vapour-liquid and liquid-liquid phase behaviour were already well characterized experimentally during the early part of this century, but the theoretical explanation of phase equilibria for a wide variety of substances and over a large range of pressures and temperatures has lagged far behind. This paper presents theoretical studies of phase equilibria in binary mixtures obeying the van der Waals equation, especially liquid-liquid equilibria that can occur at high pressures. The variety of fluid phase behaviour that occurs in binary mixtures can be qualitatively discussed in terms of the changes in thermodynamic properties near critical points. Upper critical solution temperatures (UCSTs) occur when a heterogeneous (two-phase) system becomes a homogeneous (one-phase) system when the temperature is raised. The maximum temperature along the temperature-mole fraction ( T, x ) coexistence curve for constant pressure is the UCST at this pressure. Lower critical solution temperatures (LCSTs) occur when a homogeneous system becomes a two-phase system when the temperature is increased. The LCST is at the minimum of the T, x coexistence curve. Thermodynamic considerations of critical points yield requirements for the curvature of the mixing functions plotted against x .

Phase Equilibria and Mechanical Properties in Multicomponent Al–Ni–X (X = Fe, Cr) Alloys

2018 ◽  
Vol 71 (11) ◽  
pp. 2819-2825
Author(s):  
Sandeep Jain ◽  
Reliance Jain ◽  
M. R. Rahul ◽  
Sumanta Samal ◽  
Vinod Kumar
Keyword(s):  
Mechanical Properties ◽  
Phase Equilibria

Alloys of the Ti-Si-Sn system (titanium corner): phase equilibria, structure, and mechanical properties

2011 ◽  
Vol 50 (7-8) ◽  
pp. 452-461 ◽  
Author(s):  
I. D. Gorna ◽  
M. V. Bulanova ◽  
K. O. Valuiska ◽  
M. D. Bega ◽  
O. Yu. Koval’ ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Equilibria
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