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Mater Sci Nanotechnol 2017
Volume 1 Issue 3
Magnetic Materials 2017
Page 94
October 09-10, 2017 London, UK
International Conference on
The behavior of diamagnetic macromolecules
in a magnetic field
S A Vshivkov
Ural Federal University, Russia
T
he effect of a magnetic field on the phase transitions,
structure, and rheological properties has been studied for
the liquid crystalline cellulose derivative – solvent systems:
hydroxyethyl cellulose – water, hydroxyethyl cellulose -
DMAA, hydroxyethyl cellulose - DMF, hydroxypropyl
cellulose - water, hydroxypropyl cellulose - DMF,
hydroxypropyl cellulose – DMAA, hydroxypropyl cellulose
– ethanol, ethyl cellulose – DMAA, cyanoethyl cellulose –
DMAA, cyanoethyl cellulose – DMF, Na-carboxymethyl
cellulose–water. Phase diagrams are constructed and the
regions of existence of isotropic and anisotropic phases and
the dimensions of macromolecules and supramacromolecular
particles in a wide composition range are determined. Under
application of magnetic field, the domain structure is formed
in solutions and the temperature–concentration region of the
liquid crystalline phase widens. The studied systems are found
to possess memory: after the magnetic field is switched off, the
orientation of macromolecules and the increased temperature
of phase transitions are preserved for many hours. As the
molecular mass of the polymer is increased, the ability of
macromolecules to orient themselves in the magnetic field
declines. The concentration dependence of supramolecular
particle radius in the presence of the magnetic field is
described by a curve with maxima. The threshold mechanism
governing the effect of magnetic field on liquid crystalline
transitions in polymer solutions has been discovered. The
critical value of magnetic intensity that brings about a shift
in boundary curves is consistent with the critical value of
Hcr necessary for the cholesteric liquid crystal – nematic
liquid crystal phase transition. Application of a magnetic field
is shown to be accompanied by an increase in the viscosity
of these systems by a factor of 1.3 – 4. The concentration
dependence of viscosity in the presence of a magnetic field is
described by curves with an extremum.
sergey.vshivkov@urfu.ruMaterials Science and Nanotechnology