Rupture and Regeneration of Colloidal Crystals As Studied by Two-Dimensional Ultra-Small-Angle X-ray Scattering

• Published in: Langmuir Vol. 22; no. 24; pp. 9843 - 9845
• Main Authors: Konishi, Toshiki, Ise, Norio
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.11.2006
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Water; Cubic crystals; Rupture; Small angle X ray scattering; Silica; Dispersion; Particle; Regeneration; Diffraction; Detector; Distribution; Microcrystal; Lattice structure
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la061247y

The structure of colloidal crystals of silica particles in water was studied by using the two-dimensional (2D) ultra-small-angle X-ray scattering (USAXS) technique. By violent shaking of the dispersion, large (body-centered cubic, bcc) crystals were broken into microcrystals while the lattice structure and lattice constant were preserved. The 2D-USAXS profiles revealed that the [11̄1] direction of bcc microcrystals was parallel to the capillary axis and their orientational distribution with respect to the capillary axis was random. While a prepeak was observed in the one-dimensional USAXS measurements, no such peak was detected by the 2D-USAXS technique. The prepeak was concluded to be due to {110} being rotated by 54.7° (the angle between [001] and [11̄1]) from the capillary axis. The diffraction from the plane was out of the horizontal plane and was observed at a lower angle as a prepeak by detector scanning in the horizontal direction.