Universität zu Köln

Koch, Karin, Kundt, Matthias, Barkane, Anda, Nadasi, Hajnalka, Webers, Samira ORCID: 0000-0002-5602-5018, Landers, Joachim, Wende, Heiko ORCID: 0000-0001-8395-3541, Eremin, Alexey ORCID: 0000-0001-9743-6895 and Schmidt, Annette M. (2021). Superparamagnetic nanoparticles with LC polymer brush shell as efficient dopants for ferronematic phases. Phys. Chem. Chem. Phys., 23 (43). S. 24557 - 24571. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 1463-9084

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Abstract

Liquid crystal (LC) based magnetic materials consisting of LC hosts doped with functional magnetic nanoparticles enable optical switching of the mesogens at moderate magnetic field strengths and thereby open the pathway for the design of novel smart devices. A promising route for the fabrication of stable ferronematic phases is the attachment of a covalently bound LC polymer shell onto the surface of nanoparticles. With this approach, ferronematic phases based on magnetically blocked particles and the commercial LC 4-cyano-4 '-pentylbiphenyl (5CB) liquid crystal were shown to have a sufficient magnetic sensitivity, but the mechanism of the magneto-nematic coupling is unidentified. To get deeper insight into the coupling modes present in these systems, we prepared ferronematic materials based on superparamagnetic particles, which respond to external fields with internal magnetic realignment instead of mechanical rotation. This aims at clarifying whether the hard coupling of the magnetization to the particle's orientation (magnetic blocking) is a necessary component of the magnetization-nematic director coupling mechanism. We herein report the fabrication of a ferronematic phase consisting of surface-functionalized superparamagnetic Fe3O4 particles and 5CB. We characterize the phase behavior and investigate the magneto-optical properties of the new ferronematic phase and compare it to the ferronematic system containing magnetically blocked CoFe2O4 particles to get information about the origin of the magneto-nematic coupling.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Koch, Karin UNSPECIFIED UNSPECIFIED UNSPECIFIED Kundt, Matthias UNSPECIFIED UNSPECIFIED UNSPECIFIED Barkane, Anda UNSPECIFIED UNSPECIFIED UNSPECIFIED Nadasi, Hajnalka UNSPECIFIED UNSPECIFIED UNSPECIFIED Webers, Samira UNSPECIFIED orcid.org/0000-0002-5602-5018 UNSPECIFIED Landers, Joachim UNSPECIFIED UNSPECIFIED UNSPECIFIED Wende, Heiko UNSPECIFIED orcid.org/0000-0001-8395-3541 UNSPECIFIED Eremin, Alexey UNSPECIFIED orcid.org/0000-0001-9743-6895 UNSPECIFIED Schmidt, Annette M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-580290
DOI:	10.1039/d1cp03005a
Journal or Publication Title:	Phys. Chem. Chem. Phys.
Volume:	23
Number:	43
Page Range:	S. 24557 - 24571
Date:	2021
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	1463-9084
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LIQUID-CRYSTALS; MAGNETIC PARTICLES; FERROMAGNETIC NANOPARTICLES; FREEDERICKSZ TRANSITION; STRUCTURAL TRANSITIONS; ORIENTATION; SUSPENSIONS; MOLECULES; COLLOIDS; SURFACE Multiple languages Chemistry, Physical; Physics, Atomic, Molecular & Chemical Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58029