ABSTRACT
Hybrid nanocomposites based on magnetic nanoparticles dispersed in liquid crystalline elastomers are fascinating emerging materials. Their expected strong magneto-elastic coupling may open new applications as actuators, magnetic switches, and for reversible storage of magnetic information. We report here the synthesis of a novel hybrid ferromagnetic liquid crystalline elastomer. In this material, highly anisotropic Co nanorods are aligned through a cross-linking process performed in the presence of an external magnetic field. We obtain a highly anisotropic magnetic material which exhibits remarkable magneto-elastic coupling. The nanorod alignment can be switched at will at room temperature by weak mechanical stress, leading to a change of more than 50 % of the remnant magnetization ratio and of the coercive field.
ABSTRACT
This work deals with the structural analysis of side-chain liquid crystalline polysiloxanes, doped with magnetic cobalt nanorods, and their orientational properties under a magnetic field. These new materials exhibit the original combination of orientational behavior and ferromagnetic properties at room temperature. Here we show that, within the liquid crystal polymer matrix, the cobalt nanorods self-assemble in bundles made of nanorod rows packed in a 2-dimensional hexagonal lattice. This structure accounts for the magnetic properties of the composites. The magnetic and orientational properties are discussed with respect to the nature of the polymer matrix.