Soft metamaterial with programmable ferromagnetism

Abstract

Magnetopolymers are of interest in smart material applications; however, changing their magnetic properties post synthesis is complicated. In this study, we introduce easily programmable polymer magnetic composites comprising 2D lattices of droplets of solid-liquid phase change material, with each droplet containing a single magnetic dipole particle. These composites are ferromagnetic with a Curie temperature defined by the rotational freedom of the particles above the droplet melting point. We demonstrate magnetopolymers combining high remanence characteristics with Curie temperatures below the composite degradation temperature. We easily reprogram the material between four states: (1) a superparamagnetic state above the melting point which, in the absence of an external magnetic field, spontaneously collapses to; (2) an artificial spin ice state, which after cooling forms either; (3) a spin glass state with low bulk remanence, or; (4) a ferromagnetic state with high bulk remanence when cooled in the presence of an external magnetic field. We observe the spontaneous emergence of 2D magnetic vortices in the spin ice and elucidate the correlation of these vortex structures with the external bulk remanence. We also demonstrate the easy programming of magnetically latching structures.

Breaking the clean room barrier: exploring low-cost alternatives for microfluidic devices

“…The trend of utilizing polymers for microfluidic device fabrication is evident in the pursuit of novel materials that can be effectively employed in microfluidic devices. For example, Kaya et al (2022) have introduced programmable polymer magnetic composites that incorporate droplets of solid-liquid phase change material, each containing a single magnetic dipole particle. These composites can be reprogrammed into four different states: superparamagnetic, artificial spin ice, spin glass, and ferromagnetic.…”

“…These composites can be reprogrammed into four different states: superparamagnetic, artificial spin ice, spin glass, and ferromagnetic. Also, they possess high remanence characteristics along with Curie temperatures below the composite’s degradation temperature ( Kaya et al, 2022 ). The development of such innovative materials offers new tools that can be utilized in microfluidics to develop advanced devices and enhance the design of labs-on-a-chip.…”