In situ small angle X-ray and neutron scattering measurements of self-assessed templates in an electric field

A chamber has been developed for in situ measurements of structural alignment of liquid crystalline templates and subsequent polymerisation with SAXS and SANS in a static electric field. The cell is designed in directions parallel and orthogonal to the electric field with conducting and non-conducting fluids. In the direction parallel to the x-ray beam the electrodes consists of a layer of conducting material and a support material. For non-conducting fluids the conductive electrode surface may be in contact with the liquid and in the case of the aqueous system we place the conductive surface on the outside to avoid electrochemical reactions. For the orthogonal field/measurement direction only an x-ray transparent window is necessary. The cell is designed to optimise the scattering signal through an adjustable thickness but also give a minimal and reproducible isotropic background signal suitable for characterising the scattering anisotropy. The cells windows must have a minimal but homogenous (for consistency of back ground subtraction) scattering signal. Ensuring constant dimensions (sample thickness and distance between electrodes) and orthogonality between x-ray beam and sample windows is important both for background subtraction and homogeneity of the electric field. For SANS measurements, the design principles are similar, but choice of materials is quite different.