Vos, W.L.; Megens, M.; van Kast, C.M.; Boesecke, P. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We have resolved a great number of Bragg peaks of photonic colloidal single crystals by synchrotron small angle X-ray scattering (SAXS). We find that charge-stabilized colloids form face-centered cubic crystals at all densities up to ∼60 vol %. The colloidal particles are highly ordered on their lattice sites, which confirms that these self-organizing materials are suitable building blocks for optical photonic matter. The experiments demonstrate that synchrotron SAXS with two-dimensional detection is a powerful tool to study systems with length scales comparable to optical wavelengths.

In Situ Characterization of Colloidal Spheres by Synchrotron Small-Angle X-ray Scattering Megens, M.; van Kast, C.M.; Boesecke, P.; Vos, W.L. Published in: Langmuir DOI:10.1021/la970422vLink to publication Citation for published version (APA):Megens, M., van Kast, C. M., Boesecke, P., & Vos, W. L. (1997). In Situ Characterization of Colloidal Spheres by Synchrotron Small-Angle X-ray Scattering. Langmuir, 13, 6120-6129. DOI: 10.1021/la970422v General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We have performed small-angle X-ray scattering with a synchrotron source on dilute suspensions of colloidal spheres of polystyrene latex, Stöber silica, and microemulsion-grown silica. Many interference fringes are observed of the monodisperse particles over a large range of scattering vectors and more than 5 orders of magnitude in intensity. We present a straightforward method to deduce the radii, the size polydispersity, and the interface thickness of the particles from a Porod plot of one and the same in situ measurement. The radii agree very well with static light-scattering data. The radii are larger than the electron microscopy data of dry spheres and smaller than the hydrodynamic radii from dynamic lightscattering data. The size polydispersities are smaller than those obtained by electron microscopy, which is well explained by the intrinsic random errors of electron microscopy. We find that nearly all the particles have a homogeneous internal density and a sharp interface with the suspending medium of less than 1 nm wide. In one case of a stepwise synthesized particle, we have discerned a dense core and a less-dense shell, without contrast matching with the suspending liquid. It is concluded that synchrotron small-angle X-ray scattering is a very powerful technique for the in situ study of colloidal systems.