uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Structure of a large colloidal crystal: controlling orientation and three-dimensional order
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
2012 (English)In: RSC Advances, ISSN 2046-2069, Vol. 2, no 18, 7091-7098 p.Article in journal (Refereed) Published
Abstract [en]

The three-dimensional crystal structure of charge stabilised polystyrene latex in deionised water was investigated by small-angle neutron diffraction. Crystallisation with a grain size of approximately 1 x 1 cm(2) was observed when the sample was flowed gently in to a 2 mm path cell. Bragg scattering peaks arising from the structure were observed under rotation about three perpendicular axes of the sample. The diffraction patterns indicate clearly that there is a cubic close packed structure with a 110 axis perpendicular to the cell wall. Rotations in small steps show large changes and indicate that the crystal is well oriented and has three-dimensional order. The crystal orientation was controlled by the meniscus and direction of flow when filling the cell.

Place, publisher, year, edition, pages
2012. Vol. 2, no 18, 7091-7098 p.
National Category
Other Physics Topics
URN: urn:nbn:se:uu:diva-171737DOI: 10.1039/c2ra21092dISI: 000306946500014OAI: oai:DiVA.org:uu-171737DiVA: diva2:512222

Original manucript title: Structure of colloidal crystal : controlling size and three-dimensional order

Available from: 2012-03-26 Created: 2012-03-26 Last updated: 2012-10-02Bibliographically approved
In thesis
1. Adsorption and Ordering of Surface Active Molecules and Particles at Solid Interfaces and in the Bulk
Open this publication in new window or tab >>Adsorption and Ordering of Surface Active Molecules and Particles at Solid Interfaces and in the Bulk
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Factors that influence the process of adsorption and order of dilute and concentrated systems of molecules and particles are explored in this thesis.  The results are based largely on neutron scattering techniques.  Study of the adsorption from dilute solutions of a common surfactant, AOT (sodium bis (2-ethylhexyl) sulfosuccinate), at a solid/liquid interface showed that AOT molecules adsorbed to the interface in a bilayer structure, with the hydrocarbon tails at maximum packing density even at very low concentrations.  At higher AOT concentrations, a stack of fluctuating layers each separated by large amounts of water next to the dense bilayer was seen.  The driving force for adsorption is dominated by self-assembly of AOT.  It was found that an oriented lamellar phase wets the interface below the bulk concentration for formation of this phase.

Proteins can be viewed as polymeric surfactants.  The adsorption of proteins from seeds of the Moringa oleifera tree to a silicon oxide surface was studied to elucidate the mechanism of the protein as a flocculent in water treatment processes.  The protein was found to adsorb at the interface as dense layers with a thickness suggestive of co-adsorption rather than single isolated molecules.  The strong adsorption and tendency to associate in solution suggest mechanisms for flocculating particulate impurities in water.

As with surfactants, dispersions of colloidal particles can assemble in regular structures by self-assembly.  Polystyrene latex particles were studied and could form large three-dimensional crystals of about 1×1 cm2 in a 2 mm path cell.  The diffraction pattern indicated a close packed structure with the 110 axis perpendicular to the container wall.  The crystal was well-aligned and oriented by the direction of flow.  At the solid interface large two-dimensional domains of about 20 cm2 of highly oriented particles were formed.  The particle-particle separation at the surface and in the bulk was determined by the charge repulsion of the particles.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 56 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 915
National Category
Condensed Matter Physics
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
urn:nbn:se:uu:diva-171739 (URN)978-91-554-8327-2 (ISBN)
Public defence
2012-05-16, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Available from: 2012-04-24 Created: 2012-03-27 Last updated: 2012-08-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Hellsing, Maja S.Rennie, Adrian R.
By organisation
Materials Physics
Other Physics Topics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 138 hits
ReferencesLink to record
Permanent link

Direct link