Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userReexamination of Tolmans law and the Gibbs adsorption equation for curved interfaces
127
0
0.0
(
0
)
Added by
Martin Thomas Horsch
Publication date
2017
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
In manuscript arXiv:1703.08719 [cond-mat.soft], it was claimed that the well-known deduction of Tolmans law is not rigorous, since Tolmans argument implies that two different definitions of the surface tension, called $gamma$ and $bargamma$ in the manuscript, coincide. This claim is retracted as it can be shown by free-energy minimization that $gamma = bargamma$ indeed holds for the Laplace radius. Joachim Gross, Philipp Rehner, Carlos Vega, O{}ivind Wilhelmsen, and the anonymous reviewers of The Journal of Chemical Physics contributed to finding the mistake in the manuscript.
rate research
Read More
We construct a mean-field formulation of the thermodynamics of ion solvation in immiscible polar binary mixtures. Assuming an equilibrium planar interface separating two semi-infinite regions of different constant dielectric medium, we study the electrostatic phenomenon of differential adsorption of ions at the interface. Using general thermodynamic considerations, we construct the mean-field $Omega$-potential and demonstrate the spontaneous formation of an electric double-layer around the interface necessarily follow. In our framework, we can also relate both the bulk ion densities in the two phases and the distribution potential across the interface to the fundamental Born free energy of ion polarization. We further illustrate this selective ion adsorption phenomenon in respective examples of fully permeable membranes that are neutral, negative, or positive in charge polarity.
The present work is trying to explain a discrepancy between experimental observations of the drainage of foam films from aqueous solutions of sodium dodecyl sulfate (SDS) and the theoretical DLVO-accomplished Reynolds model. It is shown that, due to overlap of the film adsorption layers, an adsorption component of the disjoining pressure is important for this system. The pre-exponential factor of the adsorption component was obtained by fitting the experimental drainage curves. It corresponds to a slight repulsion, which reduces not only the thinning velocity as observed experimentally but corrects also the film equilibrium thickness.
We analyze spin-dependent carrier dynamics due to incoherent electron-phonon scattering, which is commonly referred to as Elliott-Yafet (EY) spin-relaxation mechanism. For this mechanism one usually distinguishes two contributions: (1) from the electrostatic interaction together with spin-mixing in the wave functions, which is often called the Elliott contribution, and (2) the phonon-modulated spin-orbit interaction, which is often called the Yafet or Overhauser contribution. By computing the reduced electronic density matrix, we improve Yafets original calculation, which is not valid for pronounced spin mixing as it equates the pseudo-spin polarization with the spin polarization. The important novel quantity in our calculation is a torque operator that determines the spin dynamics. The contribution (1) to this torque vanishes exactly. From this general result, we derive a modified expression for the Elliott-Yafet spin relaxation time.
The effects of contact-line pinning are well-known in macroscopic systems, but are only just beginning to be explored at the microscale in colloidal suspensions. We use digital holography to capture the fast three-dimensional dynamics of micrometer-sized ellipsoids breaching an oil-water interface. We find that the particle angle varies approximately linearly with the height, in contrast to results from simulations based on minimization of the interfacial energy. Using a simple model of the motion of the contact line, we show that the observed coupling between translational and rotational degrees of freedom is likely due to contact-line pinning. We conclude that the dynamics of colloidal particles adsorbing to a liquid interface are not determined by minimization of interfacial energy and viscous dissipation alone; contact-line pinning dictates both the timescale and pathway to equilibrium.
Curved fluid interfaces are investigated on the nanometre length scale by molecular dynamics simulation. Thereby, droplets surrounded by a metastable vapour phase are stabilized in the canonical ensemble. Analogous simulations are conducted for cylindrical menisci separating vapour and liquid phases under confinement in planar nanopores. Regarding the emergence of nanodroplets during nucleation, a non-equilibrium phenomenon, both the non-steady dynamics of condensation processes and stationary quantities related to supersaturated vapours are considered. Results for the truncated and shifted Lennard-Jones fluid and for mixtures of quadrupolar fluids confirm the applicability of the capillarity approximation and the classical nucleation theory.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
