In
soap films, two types of
equilibrium film are often observed, sometimes successively in the same system: one characterized
by thicknesses of the order of
or more which varies significantly with minor changes in composition such as
ionic strength, and the other having a lesser thickness relatively independent of such changes.
When a distinction is needed, the former are designated as
common black films, and the latter as
Newton black films. The current use of first or secondary for the
common black film and of second, primary or Perrin's for the
Newtonblack film is discouraged.
Source:
PAC, 1972, 31, 577
(Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix
II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry)
on page 614
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
