ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The binding of 41-(1-pyrenyl)butyltrimethylammonium bromide (PN+) to the neutral poly-soap-type polymers poly(vinylbenzo-18-crown-6) (P18C6) and poly(vinylbenzoglyme) (PVBG) was studied by optical spectroscopy and fluorescence in the presence and absence of salts. Measurements of the respective binding constants were based on distinct differences in the optical absorption spectra of free and polymer-bound PN+. When crown ether-compelxable cations (e.g., K+) were added the adsorption of PN+ to P18C6 decreased as the neutral polymer was converted to a polycation. No decrease was found with PVBG because alkali ions do not complex significantly to this polymer in water. PN+ adsorption to both polymers rose rapidly, however, as the salt concentration increased. This effect was strongly anion-dependent and increased in the order of Cl- 〈 Br- 〈 I- 〈 CNS- 〈 BPh4-. The increased binding was reflected in a higher binding constant and also in a larger number of bound PN+ molecules per polymer chain under saturation conditions. It is argued that the formation of ion pairs or larger ion clusters in the aqueous phase when anions are added forces more PN+ molecules to adsorb on the surface of the polymer coil to which they are bound as ion pairs or higher aggregates. Under saturation conditions enough PN+ molecules are bound to convert the pyrene monomer fluorescence spectrum into that of the excimer. These results are compared with data obtained for the anionic solute 4-(1-pyrenyl)butanoate in the presence of salts.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1984.170221123
