Ferrofluid high internal phase emulsion polymer foams for soft, magnetic materials

Bury, Elizabeth; Thiagarajan, Sandhiya; Lazarus, Nathan; Koh, Amanda

doi:10.1016/j.jmmm.2022.169921

Cited by 5 publications

(2 citation statements)

References 64 publications

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“…The magnetization of the bare fabric (black) is negligible compared to that of ferro uid (green) and Ferrofabric (red). The low hysteresis observed in the M-H curves of the ferro uid and the Ferrofabric indicates low loss and therefore, suitability for AC applications 54 . The relative magnetic permeability , with χ being the magnetic susceptibility (i.e., the slope of the M-H curves), of the ferro uid and the Ferrofabric are extracted to be 16.6 and 11.3, respectively (Fig.…”

Section: Ferrofabric As a Stretchable Magnetic Backplanementioning

confidence: 93%

A Wearable and Unobstructive Qi-Compatible Wireless Charger

Lu,

Kim,

Wells

et al. 2023

Preprint

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Wearable wireless power transfer (WPT) systems offer untethered charging of wearable, implantable, and even mobile devices on the go, but face challenges in safety, efficiency, and wearability. We introduce a thin, stretchable, and safe hand band capable of watt-level wireless charging through the Qi protocol. The implementation of non-adhesive fabric encapsulation serves to protect the thin and spiral copper antenna from mechanical strain, ensuring an overall stretchability of 50%. We also created a stretchable “Ferrofabric”, characterized by a magnetic permeability of 11.3 and a tensile modulus of 75.3 kPa, that provides magnetic shielding for the antenna without compromising wearability. By addressing loss mechanisms such as the skin effect, proximity effect, core loss, and joule heating, we achieved a wireless charging efficiency of 72% and power delivery of 3.81 W in the kHz frequency range. Our WPT hand band is unobstructive to hand motion and can charge a handheld smartphone as fast as a desktop charger or power a battery-free chest-laminated e-tattoo, both with well-managed thermal and electromagnetic safety. Through a holistic electromagnetic, structural, and thermal design, our device culminated in a safe, rugged, and versatile solution for wearable WPT systems.

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Section: Ferrofabric As a Stretchable Magnetic Backplanementioning

confidence: 93%

A Wearable and Unobstructive Qi-Compatible Wireless Charger

Lu,

Kim,

Wells

et al. 2023

Preprint

Self Cite

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“…The evolved CO 2 gas trapped in the monolith expanded upon reduced pressure, resulting in materials with volume expansion of up to ∼30 times without total rupture of the surrounding PDMS network. Maintaining the dispersed phase liquid within the PDMS-polyHIPE has been used in applications such as ferrofluid-filled magnetic elastomers, 78 liquid-reinforced elastomers, 79 and synthetic plant tissue. 80 In synthetic plant tissue analogues (PTA), the initial dispersed phase consisted of aqueous salt solutions of various salt concentrations that experienced osmotic-induced swelling when submerged in pure water ( Figure 12 ).…”

Section: Siliconesmentioning

confidence: 99%

Synthesis and Applications of Elastomeric Polymerized High Internal Phase Emulsions (PolyHIPEs)

McKenzie

Ayres

2023

ACS Omega

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Polymer foams (PFs) are among the most industrially produced polymeric materials, and they are found in applications including aerospace, packaging, textiles, and biomaterials. PFs are predominantly prepared using gas-blowing techniques, but PFs can also be prepared from templating techniques such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPEs have many experimental design variables which control the physical, mechanical, and chemical properties of the resulting PFs. Both rigid and elastic polyHIPEs can be prepared, but while elastomeric polyHIPEs are less commonly reported than hard polyHIPEs, elastomeric polyHIPEs are instrumental in the realization of new materials in applications including flexible separation membranes, energy storage in soft robotics, and 3D-printed soft tissue engineering scaffolds. Furthermore, there are few limitations to the types of polymers and polymerization methods that have been used to prepare elastic polyHIPEs due to the wide range of polymerization conditions that are compatible with the polyHIPE method. In this review, an overview of the chemistry used to prepare elastic polyHIPEs from early reports to modern polymerization methods is provided, focusing on the applications that flexible polyHIPEs are used in. The review consists of four sections organized around polymer classes used in the preparation of polyHIPEs: (meth)acrylics and (meth)acrylamides, silicones, polyesters and polyurethanes, and naturally occurring polymers. Within each section, the common properties, current challenges, and an outlook is suggested on where elastomeric polyHIPEs can be expected to continue to make broad, positive impacts on materials and technology for the future.

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