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X-Ray diffraction and AFM at the Cebe Lab

Wide and small angle X-ray scattering (WAXS and SAXS) are used by the Cebe Research Group to investigate the crystalline unit cell, degree of crystal perfection, phase structure and lamellar nature of periodic crystalline stacks. Example of wide-angle scattering pattern is shown below for isotactic polystyrene, ranging from non-crystalline (curve 1) up to highly crystalline (curve 5). The Miller Indices for the scattering peaks are listed above the peaks. The ratio of the area under the coherent scattering peaks to the total scattered intensity is used to determine the degree of crystallinity, and compared to other measurement derived from thermal or infrared analyses. Two dimensional WAXS and SAXS images are shown in the second row, for polypropylene films oriented by shear (direction of shear is shown by the arrows). Not only are the unit cells of crystallites oriented (WAXS-left hand side), but the polymer lamellae are as well (SAXS-right hand side).

data student at Brookhaven Lab
Graduate student, Qian Ma, is shown at the Brookhaven National Synchrotron Light Source, beamline X27C, where she performs real-time simultaneous X-ray scattering and dielectric relaxation studies.
diffraction pattern
diffraction pattern

AFM image of spherulites students afm
Graduate students using the atomic force microscope.