ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Three synthetic α-polypeptides were spread on aqueous substrates from suitable molecular solutions, and the surface areas, pressures, compressibilities, etc. measured on a horizontal film balance. On pure water spreading occurred at the best in the form of condensed films, but on aqueous solutions spreading improves with the solute concentration, especially near saturation of lyotropic compounds such as urea or potassium thiocyanate. On such substrates molecular weights (MW) and surface areas (SA) can be calculated by means of a modified van der Waals' equation. The MW and SA obtained as a function of substrate nature are found to be functionally related. The conditions and assumptions under which such a relation may be used to decide on true MW's, and their pertinence for the above polypeptide data, are discussed. Di- and trivalent cations in the substrate are found to increase MW's in accordance with their valence.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1955.120168227
