Ferrogel: a new magneto-controlled elastic medium

Abstract

Magnetic-field-sensitive gels, called ferrogels, have been prepared by introducing monodomain, magnetite particles of colloidal size into chemically crosslinked poly(vinyl alcohol) hydrogels. The influence of a non-uniform external magnetic field on the shape of gel tubes and the possibility to induce elongation and contraction by means of a magnetic field gradient produced by an electromagnet have been demonstrated. It was shown that both the concentration of magnetite particles and the crosslinking density of the ferrogels play an essential role in the magneto-elastic behaviour.