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.
Surface Tension and Surface Roughness of Supported Polystyrene Films
Surface-diffuse X-ray scattering has been measured from a series of polystyrene (PS) films supported on oxide-terminated Si substrates. Films of thicknesses ranging from 84 to 359 nm were investigated over a temperature range from 120 to 180 °C, all above the bulk PS glass transition temperature. The surface tension was extracted from the absolute intensity of diffuse scattering. The values show a slight excess of the surface tension (∼20%) over the bulk material. Capillary wave theory is used to describe the observed diffuse scattering down to in-plane length scales of 2 nm, the limit of our resolution. The total surface roughness exceeds the value that would be expected from capillary wave theory, indicating the presence of excess roughness at length scales less than 2 nm.
FlowBrush: optical flow art
The depiction of motion in static representations has a long tradition in art and science alike. Often, motion is depicted by spatio-temporal summarizations that try to preserve as much information of the original dynamic content as possible. In our approach to depicting motion, we remove the spatial constraints and generate new content steered by the temporal changes in motion. Applying particle steering in combination with the dynamic color palette of the video content, we can create a wide range of different image styles. With recorded videos, or by live interaction with a webcam, one can influence the resulting image. We provide a set of intuitive parameters to affect the style of the result, the final image content depends on the video input. Based on a collection of results gathered from test users, we discuss example styles that can be achieved with FlowBrush. In general, our approach provides an open sandbox for creative people to generate aesthetic images from any video content they apply.