Figure 7.
(a) Storage modulus as a function of shear strain amplitude (constant frequency of 1 Hz) of magnetic hydrogels with 5 vol.% of FeCC magnetic particles. Open square, non-magnetic hydrogel. Filled square, magnetic hydrogels gelled in the absence of magnetic field. Right side filled square, magnetic hydrogels with ‘perpendicular’ anisotropy. Left side filled square, magnetic hydrogels with ‘aligned’ anisotropy. Bullet symbols refer to data taken during the application of an external magnetic field of H = 282 kA m−1, while squares refer to measures without an external magnetic field applied. (b,c) Optical microscopy images of a diluted magnetic hydrogel with FeCC particles. (b) Line of observation perpendicular to the direction of anisotropy—note the filament-like pattern. (c) Line of observation parallel to the direction of anisotropy—note the irregular spots, likely associated with the existence of percolating chain-like structures. (Online version in colour.)