Magnetic Field Sensitive Polymeric Actuators

Abstract

This paper reports on the magnetoelastic properties of a recently developed soft and wet material; the magnetic field sensitive polymer gel. It is a polymer network swollen by a ferrofluid. The peculiar magnetoelastic properties may be used to create a wide range of motions and to control the shape change and movement. An understanding of magnetoelastic coupling in gels will hasten the application of gel engineering to switches, sensors, micromachines, biomimetic energy-transducing devices and controlled delivery systems.

Novel Coiling Behavior in Magnet‐Polymer Composites

“…The response time of the samples to the change in magnetic field is less than 60 ms, in agreement with a previous study which reported a response time under 100 ms. [14] The dynamic properties of Magpol in elongation mode were studied using a different electromagnet, deformation of more than 24 000 cycles at 80 Hz can be achieved without a significant shift in strain-field characteristics. In general, it is known that field driven actuators like Magpol have fast switching time and better service life than ionic actuators.…”

“…This type of magneticpolymer composite (Magpol), also termed ferrogel, [1][2][3][4][5][6][7][8] magnetic gels, [9,10] magnetic field sensitive gel, [11][12][13][14][15][16] magnetorheological elastomer, [17,18] or magnetoactive polymer, [19] can readily change its shape and mechanical properties upon exposure to an external magnetic field. Many applications have been identified for Magpol including controllable dampers, [20] stiffness tunable supports, [21] miniature fluid pumps, [22] drug delivery, [23] cancer treatment, [23] sensors, [24,25] soft transducers, and artificial muscles.…”

“…This movement of the composite is due to the strong interfacial adhesion between the magnetic particles and the polymer chains in the matrix. [12] Reported modes of shape change in Magpol include deflection, [27] elongation, [14,28] and contraction. [29] Shape change behavior of Magpol can be used for soft actuation, the behavior can be tuned by geometrical and material parameters to exhibit mechanical transition analogous to first or second order phase transformation, hence Magpol can be used for both linear and switching (i.e., on-off) applications.…”

“…[29] Shape change behavior of Magpol can be used for soft actuation, the behavior can be tuned by geometrical and material parameters to exhibit mechanical transition analogous to first or second order phase transformation, hence Magpol can be used for both linear and switching (i.e., on-off) applications. [30] Previous work has shown that strains of up to 40% [14] and stress of up to 6.8 kPa [28] could be achieved in elongation mode for a composite of poly(vinyl alcohol) gel and Fe 3 O 4 particles. In contraction mode, Magpol was modeled to mimic muscular actuation and shown to produce work of up to 7 mJ.…”

“…In contraction mode, Magpol was modeled to mimic muscular actuation and shown to produce work of up to 7 mJ. [31] In this work, the actuation behavior of Magpol in a compressive magnetic field was studied. Different actuation modes were achieved simply by changing the position of the sample with respect to the magnetic field or by controlling the sample deformation in the radial direction ( Figure 1).…”