Synthesis, structure and properties of coagulated ultrathin membranes

Abstract

The Coulomb interactions between charged surfactants and multivalent counter‐ions can be used to form coagulated cross‐linked membranes at the surface of water. We have systematically measured the kinetics of the two‐dimensional gelation and the rheological properties of the stabilized films. The membranes, thus prepared, exhibit striking rubber‐elastic features. The results of Brewster‐Angle‐Microscopy indicate that these films consist of disc‐like aggregates, having typical diameters of about 10 μm. These particles are in close contact and form fractal network clusters. The shape of these structures is in general agreement with aggregates calculated from percolation theories.

Deformation and bursting of nonspherical polysiloxane microcapsules in a spinning-drop apparatus

“…In these experiments it was also possible to explore the regime of linear viscoelasticity and critical shear stress [10,13]. In addition to these investigations, one could also visualize these ultrathin cross-linked films using Brewster Angle and video-enhanced microscopy [9,10,14,15]. Parallel to these investigations we can use special computer programs as molecular dynamics, force field methods or dissipative particles dynamics (DPD) to calculate microscopic structures and physical properties as interfacial tensions [16,17].…”

Structure and Properties of Calcium Pyruvate in Aqueous Solutions

“…This solution behaviour has neither been observed for the corresponding Na ϩ or K ϩ salts of pyruvate, nor for pyruvate solutions in the presence of Mg 2ϩ , and may play a physical-chemical role in regulating red Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/11/15 1:53 AM cell deformation [17] and neuronal networks [5]. Moreover, a different form of film network has been recently reported by Rehage et al of surfactants in the presence of Ce 4ϩ salts or Al 3ϩ [18].…”

STATISTICAL MECHANICS OF SELF-AVOIDING CRUMPLED MANIFOLDS — Part II

“…As can be seen in the set of lectures in this volume, which presents an extended version of [1], the statistical mechanics of random surfaces and membranes, or more generally of extended objects, poses fundamental problems. The study of polymerized membranes, which are generalizations of linear polymers [2,3] to two-dimensionally connected networks, is emphasized, with a number of possible experimental realizations [4,5,6,7,8], or numerical simulations [9,10]. From a theoretical point of view, a clear challenge in the late eighties was to understand self-avoidance (SA) effects in membranes.…”