We report on a new application of the X-ray Surface Forces Apparatus [1] [2] [3] [4] (XSFA) to the study of the alignment of complex fluid thin films under confinement and/or flow using synchrotron X-ray scattering. The smectic A liquid crystal 8CB (4-cyano-4 -octylbiphenyl) and the hexagonal phases of a zwitterionic polyisoprene melt and of a lyotropic liquid crystal composed of sodium dodecyl sulfate (SDS), pentanol and water were investigated in the regime where the distances between the

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... ining surfaces range from 0.4 to tens of microns. In this paper, we demonstrate that this new technique allows preparation of highly-oriented complex fluid samples suitable for high resolution X-ray diffraction and scattering studies. In addition, we have directly measured forces across thin films of 8CB using the conventional Surface Forces Apparatus (SFA). The force measurements complement well the direct X-ray imaging and provide indirect information on the sample alignment in films a few tens ofÅngströms thick. (