Electric and Magnetic Field Studies on Rodlike fd-Virus Suspensions

Abstract

The electrical and optical properties of rodlike fd-virus particles (L = 880 nm, D = 9 nm) are investigated by magnetic and electric birefringence experiments and supplemented by electric field light-scattering measurements. In aqueous suspension the fd-virus particles are negatively charged and surrounded by diffuse counterion clouds. The examinations are performed at very low ionic strength (10"6 M). Under these conditions a liquid crystalline phase already occurs at fd-particle concentrations above 0.6 mg/mL. In magnetic fields the rodlike fd-virus is aligned parallel to the magnetic field due to its diamagnetic anisotropy. Almost complete particle alignment in magnetic fields is obtained for liquid crystalline samples, and the saturation value of the birefringence is determined. The application of electric fields results in a polarization of the counterion clouds and a statistical orientation of the dispersed particles. In low electric fields Kerr behavior is found, providing the electric anisotropy Aotet of a single rod. At higher electric fields the diffuse Debye cloud is partly stripped away and a complete particle orientation is hindered. Electric field light-scattering investigations yield quantitatively the decrease of the electric anisotropy Aoiei in high electric fields.

Density functional theory for hard spherocylinders: phase transitions in the bulk and in the presence of external fields

“…The angle between ω and ω 0 is denoted by θ in the following. This type of interaction which is certainly the dominating term in any orientational coupling has been considered previously to model rod-like polyelectrolytes in an external electric field [24]. We remark that the limit U 0 → ∞ reduces the model to that of strictly aligned rods.…”

Magnetic Field Orientation of Liquid Crystalline Epoxy Thermosets

“…Magnetic field effects on polymers are well-known, and a number of publications and reviews describe the use of magnetic fields to orient polymers. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In almost every case the materials of interest have been liquid crystals. The cooperative nature of molecular motions in a liquid crystalline phase is required to obtain orientation at realistic field strengths.…”

“…Magnetic fields are fundamentally different from flow in that the effective field strength does not decrease in the center of the sample. Magnetic field effects on polymers are well-known, and a number of publications and reviews describe the use of magnetic fields to orient polymers. − In almost every case the materials of interest have been liquid crystals. The cooperative nature of molecular motions in a liquid crystalline phase is required to obtain orientation at realistic field strengths.…”

The average magnetic anisotropy of polystyrene in polymersomes self-assembled from poly(ethylene glycol)-b-polystyrene

“…25 MB has been used to determine the magnetic alignment of a wide variety of biological and organic structures. 26–30…”