Axial strain of ferrogels under cyclic magnetic fields

Abstract

Ferrogels are low stiffness polymer materials with embedded magnetic powder filler, giving them the capability to strain in a magnetic field. The large strains, high energy densities and fast responses that have been reported make these materials attractive for actuator applications; however, a full understanding of the dynamic behavior is lacking. This paper presents an experimental study of the cyclic behavior of these materials under various frequencies in both the upright and inverted configurations. A 1D phenomenological magneto-viscoelastic model is developed and used to capture this behavior. The trends in stiffness, viscosity and density are described and then used to predict the amplitude of the strain at different frequencies.

Magnetic properties study of iron-oxide nanoparticles/PVA ferrogels with potential biomedical applications

“…The coupling between the soft elastic medium and the magnetic NPs allows the manipulation of the volume and shape of the ferrogels through the application of external magnetic fields. The effects of the magnetic fields on strain (Faidley et al 2010), shape (Raikher and Stolbov 2005;Zrínyi et al 1997), water retention François et al 2007), stiffness (Mitsumata et al 1999), and the effect of the polymeric matrix on the structural and magnetic properties (Longo et al 2012) have been reported. Because of these properties, ferrogels have many potential applications in the fields of pharmaceutics and medicine as biomembranes, biosensors, artificial muscles, and matrices for drug delivery, among others (Furukawa et al 2003;Gonzalez et al 2012;Liu et al 2006;Mao et al 2005;Miyata et al 2002;Pich et al 2004;Qiu and Park 2001;Sivudu and Rhee 2009).…”

Mechanics of magneto-active polymers

“…Jolly et al, 1996), carbonyl iron powder (e.g. Varga et al, 2006;Faidley et al, 2010), and nanoscale iron particles (Zrí nyi et al, 1996;Zhao et al, 2011). The behavior of MAPs interacting with external magnetic fields can be understood by considering the behavior of the filled particles when exposed to a field and constrained by the matrix materials simultaneously.…”

“…These magnetocontrolled soft and swellable gels are promising materials in the growing family of stimuli-responsive gels and actuators. In the past decades, ferrogels have received developments on a variety of changes in shape (Zrí nyi et al, 1996;Snyder et al, 2010a;2010b), water retention (Liu et al, 2006a;Filipcsei et al 2007;Herná ndez et al, 4 2010), stiffness (Misumata et al, 1999;Varga et al 2006) and viscoelasticity (Zrí nyi et al, 1998;Herná ndez, 2004;Herná ndez et al, 2010;Faidley et al, 2010) under magnetic fields.…”

“…For examples, strains up to 40% are reported in a ferrogel formed of PVA crosslinked with glutardialdehyde (GDA) and swollen with a ferrofluid under non-uniform magnetic field of 0.8T (Zriyi et al, 1996); dynamic study on a ferrogel synthesized with PVA gel with carbonyl iron power shows its rate-dependent deformation under a non-uniform field saturates at about 1 Hz (Faidley et al, 2010). When the gel matrix is made to be porous, ferrogel-based magnetic foams are developed (Liu et al, 2006a).…”

“…The deformation of ferrogels in a uniform magnetic field has also been demonstrated (Raikher et al, 2008;Filipcsei and Zrí nyi, 2010). The large deformation capability has made ferrogels a promising material for soft actuators and sensors (Ramanujan et al, 2006;Monz et al, 2008;Qin et al, 2009;Faidley et al, 2010). The current Chapter will focus on the magnetic-field-induced large deformation of ferrogels.…”