Streaming Birefringence Study of the Interactions of Submicroscopic Particles

Citation

Intaglietta, Marcos (1963) Streaming Birefringence Study of the Interactions of Submicroscopic Particles. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/G7G4-1K34. https://resolver.caltech.edu/CaltechTHESIS:04232012-082753882

Abstract

An apparatus for the observation of streaming birefringence with photoelectric detection, in which the output signal near the null is linear with respect to the angular distance to the null, was built and tested. It was found that such an apparatus is able to establish the position of the isocline with an accuracy of one degree for a relative retardation of 10^(-9).

The apparatus was subsequently used to study the streaming birefringence of tobacco mosaic virus and of mixtures of tobacco mosaic virus and southern bean mosaic virus. Accurate measurements of the angle of isocline of both types of solutions showed that no significant difference exists between the experimental and theoretical results, once all the sources of extraneous birefringences are accounted for.

The amount of retardation of the mixtures was found to be lower than that for pure tobacco mosaic virus at equal concentrations of the latter and equal velocity gradients. This experimental result is explained by considering that the random motion of the spherical particles interacts with the orderly rotation of the rod-like particles, decreasing the amount of aligned material, and thus the amount of retardation.

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