Particle Dynamics in a Diblock-Copolymer-Based Dodecagonal Quasicrystal and Its Periodic Approximant by X-Ray Photon
Andreas J Mueller1, Aaron P Lindsay1, Ronald M Lewis2
1Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
X-ray photon correlation spectroscopy (XPCS) revealed faster structural dynamics in dodecagonal quasicrystals compared to σ phase approximants. These findings in block copolymer blends offer new insights into soft material dynamics.
Area of Science:
- Soft matter physics
- Polymer science
- Materials science
Background:
- Block copolymer blends can self-assemble into complex ordered structures.
- Understanding the dynamics of these structures is crucial for material applications.
- Quasicrystals and approximants represent unique self-assembled phases.
Purpose of the Study:
- To investigate the temperature-dependent dynamics of a binary diblock-copolymer blend.
- To compare the structural relaxation dynamics between a dodecagonal quasicrystal and a Frank-Kasper σ phase.
- To elucidate the origins of observed dynamical differences.
Main Methods:
- Utilized temperature-dependent x-ray photon correlation spectroscopy (XPCS).
- Analyzed Bragg scattering from self-assembled diblock-copolymer structures.
- Measured structural relaxation times as a function of wavevector and temperature.
Main Results:
- Structural relaxation times were independent of the Bragg scattering wavevector.
- Dynamics were approximately 5 times faster in the dodecagonal quasicrystal phase compared to the σ phase.
- Minimal temperature dependence was observed for the relaxation times in both phases.
Conclusions:
- Dynamical relaxations are attributed to particle motion at grain boundaries in these tetrahedrally close-packed assemblies.
- XPCS successfully measured unprecedented particle dynamics in ordered soft materials.
- This work expands the utility of XPCS for studying dynamics in complex soft matter systems.
More Related Videos
11:27Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2
Published on: December 8, 2016
10:35Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Related Concept Videos
02:18X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:10X-ray Diffraction of Biological Samples
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal...
02:32The de Broglie Wavelength