In this work we describe a soft and ultrastretchable fiber with a magnetic liquid metal (MLM) core for electrical switches used in remote magnetic actuation. MLM was prepared by removing the oxide layer on the liquid metal and subsequent mixing with magnetic iron particles. We used SEBS (poly[styrene-b-(ethylene-co-butylene)-b-styrene]) and silicone to prepare stretchable elastic fibers. Once hollow elastic fibers form, MLM was injected into the core of the fiber at ambient pressure. The fibers are soft (Young’s modulus of 1.6~4.4 MPa) and ultrastretchable (elongation at break of 600~5000%) while maintaining electrical conductivity and magnetic property due to the fluidic nature of the core. Magnetic strength of the fibers was characterized by measuring the maximum effective distance between the magnet and the fiber as a function of iron particle concentration in the MLM core and the polymeric shell. The MLM core facilitates the use of the fiber in electrical switches for remote magnetic actuation. This ultrastretchable and elastic fiber with MLM core can be used in soft robotics, and wearable and conformal electronics.
Liquid metal is a promising conductor material
for producing soft and stretchable circuit “boards”
that can enable next-generation electronics by electrically connecting
and mechanically supporting electronic components. While liquid metal
in general can be used to fabricate soft and stretchable circuits,
magnetic liquid metal is appealing because it can be used for self-healing
electronics and actuators by external magnetic fields. Liquid metal
can be rendered into particles that can then be used for sensors and
catalysts through sonication. We used this feature to produce “novel”
conductive and magnetic particles. Mixing ferromagnetic iron particles
into the liquid metal (gallium) produces conductive ferrofluids that
can be rendered into gallium-coated iron particles by sonication.
The gallium shell of the particles is extremely soft, while the rigid
iron core can induce high friction in response to mechanical pressure;
thus, hand-sintering of the particles can be used to directly write
the conductive traces when the particles are cast as a film on elastic
substrates. The surface topography of the particles can be manipulated
by forming GaOOH crystals through sonication in DI water, thus resulting
in nonwettable circuit boards. These gallium-coated iron particles
dispersed in uncured elastomer can be assembled to form conductive
microwires with the application of magnetic fields.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.