J.Wagner: Dynamics of shape anisotrop magnetic particles in complex matrices
Description
Aim of the project is the investigation of dynamic properties of anisotropic magnetic particles with tunable aspect ratio in complex matrices consisting of colloidal particles and hydrogels. Anisotropic, spindle-shaped hematite particles align at magnetic flux densities of several millitesla with their principal axis perpendicular to an external field [1].
Due to direction dependent friction coefficients the mobility of the particles differ for diffusive motions parallel and perpendicular to an external field [2]. Hence, the rheological properties of such suspensions can be influenced by external fields.
Suspensions of charged colloids and hydrogels containig charged subunits will act as matrices. Particle-matrix interactions will be tuned by the volume fraction and ionic strength. In the focus of the project are correlations between the mesoscale structure and dynamics as well as field-induced changes of macroscopic properties, e. g., the complex viscosity. The access to mesoscale structure and dynamics will be given by means of static and dynamic scattering experiments while magnetorheological experiments will be used to characterize the macroscopic behavior of hybrid materials in external fields.
TEM Micrograph of spindle shaped hematite particles (top); small angle scattering of aligned hematite spindles (bottom)
Project Manager
Prof. Dr. Joachim Wagner, Universität Rostock
Staff
Annemarie Nack, Universität Rostock
Grant period
Publications
[1] C. Märkert, B. Fischer, J. Wagner, Small-angle scattering from spindle-shaped colloidal hematite particles in external magnetic fields, Journal of Applied Crystallography, 44, 441-447 (2011)
[2] J. Wagner, C. Märkert, B. Fischer, L. Müller, Direction Dependent Diffusion of Aligned Magnetic Rods by Means of X-Ray Photon Correlation Spectroscopy, Phys. Rev. Lett., 110, 048301 (2013)
Contact
Universität Rostock
Physikalische Chemie - Komplexe molekulare Systeme
Dr.-Lorenz-Weg 1
D-18051 Rostock