X-ray waveguides and thin macromolecular films

We report waveguide-enhanced X-ray experiments on thin macromolecular films, such as spin-coated polymer films, self-assembled polyelectrolyte layers, and lipid membranes, prepared on solid surfaces. Upon the deposition of an additional thin inorganic (metal) layer on top of the film (cap layer), X-ray waveguide structures can be obtained. Shining a highly brilliant X-ray beam onto the system, resonantly enhanced and precisely defined standing wave field distributions (modes) are excited. Different applications of waveguiding effects to the study of macromolecular films are discussed: (i) Waveguide-enhanced scattering, where the in-plane structure of the film is studied by grazing incidence diffraction under simultaneously excited modes, (ii) waveguide-enhanced X-ray fluorescence, and (iii) coherent scattering methods based on the coherence properties of the waveguide