ABSTRACT
Carbon fibers were tightened to a metal frame using dental cement. Droplets of polymer melts (as shown in Fig. 13) can be prepared by first dipping a tightened fiber into the polymer powder, followed by slowly heating the “powdered” fiber in a hot stage to melt the polymer. Droplets form on the fiber from a receding movement and, therefore, the measured contact angles are (or approaching) their receding angles. The drop images were recorded using a microscope equipped with a digital camera. The images shown here were taken from above (i.e., top view) and it was ensured that all fibers were
lying horizontally, perpendicular to the microscope lenses. The drop profiles were extracted from the images using a subpixel routine, as for instance described in Ref. 35. The extracted profiles (Fig. 14) were then used for calculating the contact angles.
