Resonantly enhanced off-specular X-ray scattering from polymer/polymer interfaces⋆
Abstract.We have used measurements of the absolute intensity of diffuse X-ray scattering to extract the interfacial tension of a buried polymer/polymer interface. Diffuse scattering was excited by an X-ray standing wave whose phase was adjusted to have a high intensity at the polymer/polymer interface and simultaneously a node at the polymer/air interface. This method permits the capillary-wave-induced roughness of the interface, and hence the interfacial tension, to be measured independently of the polymer/polymer interdiffusion.
Interface properties of blends of incompatible polymers
Abstract Neutron reflectometry is used to study the interface in blends of the partially compatible polymers deuterated polystyrene (PSd) and poly(styrene-co-4-bromo-styrene) (PB x S). The degree of bromination x controls the miscibility of the polymers. It is varied in a wide range in order to obtain information on the dependence of the interface width l on the compatibility of the components as expressed by the Flory Huggins interaction parameter χ. The kinetics of interface formation and the equilibrium values of l and χ as a function of bromination are discussed and compared to current theories.
Mean field model of a game for power
Abstract Our aim is to model a game for power (equivalent to total energy) as a dynamical process, where an excess of power possessed by a player allows him to gain even more power. Such a positive feedback is often termed as the Matthew effect. Analytical and numerical methods allow to identify a set of stationary states, i.e. fixed points of the model dynamics. The positions of the unstable fixed points give an insight on the basins of attraction of the stable fixed points. The results are interpreted in terms of modeling of coercive power.