Particle size distributions from transient electric birefringence data: I. polydisperse rods by two-parameter distribution functions

✍ Scribed by V.J. Morris; A.R. Foweraker; B.R. Jennings

• Publisher: Elsevier Science
• Year: 1978
• Weight: 723 KB
• Volume: 12
• Category: Article
• ISSN: 0378-4487
• DOI: 10.1016/0378-4487(78)80013-2

✦ Synopsis

Many dilute solutions or suspensions of rod-like particles become birefringent when subjected to electric fields.

On switching off the applied field the birefringence decays away as the particles revert from an ordered to a random orientation state. For polydisperse suspensions it is possible to evaluate well defined, experimental average values <D)

of the rotary diffusion constant D by an analysis of the decay process.

The nature of the average depends on the electrical and geometrical properties of the particle, on the experimental conditions of orientation and on the particle size distribution. Experimentally two such averages may always be isolated.

A method is described whereby, if the particle size distribution is describable by a two-parameter distribution function f(l) then the parameters of jc0 may be readily evaluated from the two measured (0) averages. Equations are presented for three skew and two symmetric standard distribution functions. A method is also described whereby the most appropriate distribution function can be identified.