Improved magneto-viscoelasticity of cross-linked PVA hydrogels using magnetic nanoparticles

Abstract

Magnetic nanoparticle (MNP) incorporation in soft host media offers great possibilities to control its properties and flow dynamics via external magnetic field. In the present work we report, synthesis of stable homogeneous crosslinked PVA hydrogels with MNP and their detailed rheological investigations in static and dynamics modes. The measurement results were fitted with the theoretical model presented for nonlinear and transient static & dynamic flow behavior. A good agreement has been observed with theoretical predictions confirming the high dispersivity and stability of these magnetic gels. MNP align themselves in the field direction, and field-induced structures produce hindrance to uniform stress flow which causes a nonlinear viscoelastic response. The substantial enhancement in viscoelastic properties in observed with incorporation of MNP. Static mode investigations show good yielding properties which increases with increase in MNP concentration whereas, dynamic mode storage/loss modulus response shows higher storage modulus than loss modulus. This enhancement indicates the dominance of solid-like nature of magnetic gel due to more significant field-induced structures over applied hydrodynamic forces. These magnetic gels show a quick response to the applied field which is established by transient viscosity response. The viscoelastic properties of these magnetic gels makes it effective and efficient solution for numerous applications in the field of engineering and biomedical.