3D-printing and characterization of magnetoresponsive ferronematic elastomers

• Applicants: Dr. Joachim Landers; Professorin Dr. Annette M. Schmidt
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 492620405

3D-printed magnetoactive liquid-crystalline polymers represent a promising new material concept, allowing for the synergistic combination of programmable geometry, (multi)stimuli responsive behavior (e.g. via optical excitation, temperature or electromagnetic fields) and tailored micro- and nanoscale order. Especially thermoplastic liquid-crystalline ionomers doped with anisotropic magnetic nanoparticles open new pathways for the development of multifunctional soft actuators and adaptive structures for applications in biomedicine, soft robotics, and intelligent reactive material systems. In the current project, we aim for the preparation and systematic characterization of 3D-printed ferronematic hybrid materials, whose macroscopic shape and microscopic structure can be precisely directed via controlled orientation of mesogenic units and magnetic nanoparticles in external fields (flow, magnetic field). Based on insights acquired within the previous project “Orientierungsphänomene in magnetischen Flüssigkristall-Hybridmaterialien”, we will develop novel 3D-inks for additive manufacturing prepared from liquid-crystalline ionomers, which allow for ideal particle-matrix-interactions, anisotropic particle dynamics, and flow- and field-induced alignment. Focus aspect of research contain the coupling of rheological material properties, particle dynamics, and macroscopic structure formation. For this purpose, high-temperature low-frequency AC-susceptibility and a custom-built Mössbauer spectroscopy flow-cell will be employed to analyze timescale and field-dependence of magnetic nanoparticle alignment under flow. The 3D-printing process is optimized to allow for the best possible control of nanoscale order parameters and their influence on the final structure. Additionally, the alignment of the magnetic doping agents during the printing process is enabled by application of external magnetic fields. Characterized prototype pieces will be studied concerning local order, ferronematic coupling, structural hierarchy, and their magnetomechanical properties via a combination of Mössbauer spectroscopy, scattering techniques (SAXS, WAXS), and mechanical methods. This project pursues the long-term goal to lay the foundation for the development of multifunctional, multiferroic hybrid materials, which can be designed to complex, functional architectures via additive manufacturing. Its results will contribute considerably to the evolution of smart material systems, which may play an essential role in future technologies like medical implants, autonomous robotics, or novel sensor mechanisms.

• DFG Programme: Research Grants