Magnet filler-polymer matrix composites (Magpol) are an emerging class of morphing materials. Applications of Magpol can include artificial muscles, drug delivery, adaptive optics and self healing structures. Advantages of Magpol include remote contactless actuation, several actuation modes, high actuation strain and strain rate, self-sensing and quick response. The actuation modes of Magpol, its dynamic properties, work output and transduction characteristics are described. Analogies between Magpol actuation and phase transformations are presented. As an illustration of Magpol actuation, a proof of concept artificial muscle is presented. Current applications and future prospects are described.

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Boneless soft robotic fingers cannot apply concentrated forces to pinch a delicate object. This letter reports a three-dimensional design of dielectric elastomer fingers with higher flexural stiffness and close to 90 voltage-controllable bending for object gripping and pinching. It makes use of tension arch flexures to elevate a pre-stretched dielectric elastomer actuator (DEA) into a roof shape and thus magnifies the tension-induced moment, 40 times higher than a flat DEA does, to bend a stiff base frame. Such fingers make normally close-grippers to lift a payload 8-9 times their weight. They also make normally open grippers that pinch a highly deformable raw egg yolk.

We have developed pH- and magnetic-responsive hydrogels that are stabilized by both covalent bonding and catechol/Fe(3+) ligands. The viscoelastic properties of the gels are regulated by the complexation valence and can be used to tune drug release profiles. The stable incorporation of magnetic nanoparticles further expands control over the mechanical response and drug release, in addition to providing magnetic stimuli-responsivity to the gels.