ISSN:
1435-1536
Keywords:
Key words Polyphosphate
;
degree of polymerization
;
electrostatic potential
;
surfactant
;
binding isotherm
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The binding behavior of dodecylpyridinium chloride to sodium polyphosphate of various degrees of polymerization (DP) was studied by means of a potentiometric titration method using a surfactant-selective electrode in the presence of 10 mM NaCl at 30 °C. Binding isotherms were analyzed by direct calculation of a matrix expressing the partition function. It is found that binding affinity depends prominently on the polymer chainlength when the DP value is less than ca. 35, but becomes nearly independent on DP thereafter. No binding was observed for linear triphosphate or cyclic trimetaphosphate anions. The picture that arises for the binding is that the polymer’s end-effect reduces the apparent cooperativity, while the hydrophobic interaction with neighboring surfactant remains constant because of the short-range nature of the interaction. The so-called end-effect is associated with a superimposition of electrostatic potentials around the polymer rods. Both the matrix method and the Satake–Yang equation were carried out for simulations, and the matrix one shows a better fitting with the experimental data for the short-chain polyelectrolyte.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003960050206
