Anisotropic Young's modulus on magnetically ordered agarose gel

The static elasticity of magnetically ordered agarose gel has been studied. Young's modulus gelled under strong magnetic fields and was measured outside of the magnetic field from the force-deformation relationships. Young's modulus increased with magnetic field strength, particularly when the deformation was parallel to the magnetic field by a factor of 2. Young's modulus and its anisotropy depend both on the concentration of gel as well as on the magnetic field. Assuming that the magnetic field dependence of the gel elasticity is mainly due to the magnetic change in entropic elasticity, we analyzed the domain ordering of agarose microquartz with microsyneresis in order to decide how to decrease entropy, which in turn would increase the elasticity. The anisotropic diamagnetic susceptibility of the domains was estimated to be (4.4 +/- 0.7)x10(-23) emu for 1% gel and (1.35 +/- 0.20)x10(-22) emu for 2% gel.