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.
Dynamics of polymer bilayer films
We report grazing incidence coherent X-ray measurements from polymer bilayers consisting of spun-cast layers of Polystyrene (PS) and Poly(4-bromo styrene) (PBrS) supported on silicon wafers. For PS/PBrS/Si bilayers, the films are stable and we are able to probe equilibrium thermal surface height fluctuations using X-ray Photon Correlation Spectroscopy (XPCS). When the layers are inverted to PBrS/PS/Si, the films de-wet. In this geometry we can measure both the non-equilibrium evolution of the film structure using time-resolved surface diffuse X-ray scattering and quasi-equilibrium fluctuations of the de-wetting film using XPCS.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.