Premium
Measurement of flow birefringence at very low velocity gradients
Author(s) -
Harrington R. E.
Publication year - 1970
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1970.360090203
Subject(s) - birefringence , flow birefringence , extinction (optical mineralogy) , chemistry , velocity gradient , range (aeronautics) , flow (mathematics) , optics , residual , mechanics , mineralogy , materials science , physics , composite material , algorithm , computer science
Instrumentation and associated techniques are described for the measurement of flow birefringence and extinction angles of high molecular weight polymer systems at extremely low velocity gradients. Precision of less than one degree in the extinction angles is obtained for birefringence smaller than 10 −11 , based upon studies of very dilute high molecular weight DNA solutions over a range of velocity gradients from 0.1 to 3 sec −1 . Extinction angles approaching 44° are also observed with at least this degree of reliability for these systems. A relatively simple method of data reduction is outlined which permits explicit correction for solvent effects and for residual instrument birefringence and background; only the latter are found to be necessary at the shear rates reported in this communication. Applicability of the techniques to other macromolecules of biological interest is discussed.