Project Details
Projekt
Magneto-elastomeric nanocomposites with supramolecular activity Part 2. Supramolecular elastomers
Applicant
Dr. Margarita Kruteva
Subject Area
Synthesis and Properties of Functional Materials
Experimental Condensed Matter Physics
Physical Chemistry of Solids and Surfaces, Material Characterisation
Preparatory and Physical Chemistry of Polymers
Experimental Condensed Matter Physics
Physical Chemistry of Solids and Surfaces, Material Characterisation
Preparatory and Physical Chemistry of Polymers
Term
from 2015 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 283337657
The aim of the project is the synthesis and consecutive investigation of magneto-elastomeric nanocomposites with supramolecular activity. The nanocomposites are composed of magnetic polymer-grafted nanoparticles and a matrix consisting of rubbery 1,4-polyisoprene (PI) or polyalkylene oxides. These hybrid materials allow classical magnetically-induced ordering effects especially at low matrix viscosities. The thereby achieved stimuli-responsive nanocomposites whose properties (i) depend on the surrounding conditions (temperature, matrix polymer properties) and (ii) can be easy controlled by external fields (magnetic, deformational). They are of particular interest in e.g. nanotechnology, nanoelectronics and optical applications. In the first period, in collaboration with Prof. H. Weller (Hamburg) we developed a synthetic procedure to obtain highly monodisperse nanoparticles consisting of a superparamagnetic iron oxide core (SPION) embedded in a polymeric shell (A. Feld et al. ACS Nano, 2017). Using a combination of scattering techniques with TEM we showed that particle agglomeration is largely absent. At present, we are working on replacing the outer PEO corona of the composite particle by rubbery polymers like PI. In collaboration with Prof. A. Schmidt (Cologne) cobalt ferrite (CoFe2O4) nanoparticles directly grafted with PI are being examined. Our scattering experiments in solution or in the solvent free state in the presence of a magnetic field demonstrated (i) chain-like ordering of the nanoparticles along the direction of the magnetic field and (ii) a pronounced magnetic scattering observed by SANS. The study of the magnetic effects (self-assembly, chain-like ordering, magnetic scattering) as a function of nanoparticle size demonstrates a lower limit to be 16 nm in diameter. In the next project period, we plan further systematic physical characterization of modified magnetic nanoparticles in both solution and polymer matrix under magnetic field conditions, augmented with the implementation of supramolecular functionality. Both matrix polymers and polymer-coated nanoparticles will be functionalized with supramolecular groups on the basis of hydrogen bonds. This will allow field-induced ordering at elevated temperatures, i.e. in the case of open supramolecular bonds. On the other hand, the induced structures can be "frozen-in" by cooling the system down into the state of closed supramolecular bonds. The matrix then becomes elastomeric and is itself composed of supramolecular units. These units self-assemble linearly and provide a control over the matrix viscosity. Alternatively, similar ordering effects will be achieved by mechanical deformation of the rubber-like nanocomposites. Together with partners we plan investigations of magnetic properties of the nanoparticles in-situ, i.e. in polymeric matrix, depending on external field and as a function of the distance between the nanoparticles, that is crucial for most applications.
DFG Programme
Priority Programmes
Co-Investigator
Jürgen Allgaier, Ph.D.
