F. Ludwig: Dynamical magnetic investigations of particle matrix interactions in magnetic hybrid materials
Description
Goal of the project is the development and establishment of measurement techniques for the comprehensive characterization of the dynamic properties of magnetic nanoparticles (MNP) in various particle-matrix hybrid systems. Such measurements aim for a better understanding of the particle-matrix interaction. Associated with the dynamic measurement methods is the development of theoretical models which self-consistently describe the magnetic response of MNPs embedded in a matrix to a magnetization pulse (magnetorelaxometry, MRX), to an ac magnetic field (AC susceptibility, ACS) as well as to a rotating magnetic field (RMF).
The dynamic magnetic measurement techniques which are available at the institute (fluxgate-MRX [1,2], ACS [3], und RMF [4]) and which cover a frequency range from sub-Hz up to a few MHz partially allow measurements at variable temperatures up to 100°C and in magnetic fields up to approximately 10 mT. These techniques are continuously refined according to the needs within the SPP1681.
Studies are performed especially on polymer solutions with various polymer chain lengths and on ferrogels (here the focus lies on the sol-gel transition and on the gelation kinetics). The variation of the sample temperature allows the thermally induced formation and release of the matrix (sol-gel transition) as well as the change of the Brownian time constant and viscosity. Particle-matrix hybrid systems from various project partners are investigated. The data recorded on polymer suspensions and on viscoelastic particle-matrix systems are used to extract (nano)viscosities and shear modules by applying proper models. Viscosity and shear modulus values are compared with data from (macro)rheological measurements. Aim is the promotion of the multiscale understanding of magnetorheological effects in order to consolidate the methodology developed on model systems and to apply it to biomedical and technological relevant systems.
Project Manager
PD Dr. Frank Ludwig, Technische Universität Braunschweig
Staff
Hilke Remmer, Technische Universität Braunschweig
Grant period
2013 -
Publications
[1] J. Dieckhoff, M. Schilling, and F. Ludwig, „Fluxgate based detection of magnetic nanoparticle dynamics in a rotating magnetic field”, Appl. Phys. Letters 99, 112501-1 – 3 (2011)
[2] H. Remmer, J. Dieckhoff, A. Tschöpe, E. Roeben, A. M. Schmidt, and F. Ludwig, “Dynamics of CoFe2O4 Single-Core Nanoparticles in Viscoelastic Media”, Physics Procedia 75, 1150-1157 (2015)
[3] J. Landers, S. Salamon, H. Remmer, F. Ludwig, and H. Wende, “Simultaneous study of Brownian and Néel relaxation phenomena in ferrofluids by Mössbauer spectroscopy”, Nanoletters 16, 1150-1155 (2016)
[4] A. Weidner, J. H. Clement, D. Eberbeck, C. Gräfe, H. Remmer, M. v. d. Lühe, R. Müller, F. Ludwig, F. H. Schacher, and S. Dutz, „Preparation of Core-Shell Hybrid Materials by Producing a Protein Corona around Magnetic Nanoparticles”, Nanoscale Research Letters 10, 282-1 - 11 (2015)
Contact
Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik
Technische Universität Braunschweig
Hans-Sommer-Straße 66
D-38106 Braunschweig