Binding of hexadecylammonium surfactants to water-soluble neutral polymers

Abstract

The binding of hexadecyltrimethylammonium bromide and hexadecyldimethyl-2-hydroxyethylammonium bromide to neutral polymers was measured by a potentiometric titration method using surfactant selective electrodes. Binding to poly(vinyl alcohol) was slightly cooperative, while that to poly(ethylene oxide) lacked the cooperativity. Poly(vinyl pyrrolidone) did not bind them at all. Binding affinity as estimated by a distribution coefficient of the cationic surfactants between the bulk and polymer phases is about 2 orders of magnitude smaller than that of anionic sodium dodecyl sulfate. The heat of binding was estimated from the temperature dependence of the distribution coefficient and found to be endothermic. It is imagined that the cationic surfactants are simply partitioned between the aqueous bulk phase and the polymer coil phase which is regarded as aqueous organic mixed solvent.

In Vitro Release Mechanisms of Doxorubicin From a Clinical Bead Drug-Delivery System

“…51 The second contribution derives from the fact that PVA is an amphiphilic polymer known to bind to the surface of regular cationic surfactant micelles in aqueous solution thereby stabilizing them. 52,53 According to Lewis et al, 17 the beads contain 96 wt% water when in equilibrium with pure water. By subtracting the weight fraction of AMPS (16 mM corresponds to 0.5 wt%), we found that the 100-300 mm fraction contained approximately 3.5 wt% PVA, corresponding to approximately 800-mM uncharged vinyl alcohol segments or approximately 50 segments per network charge.…”

Surfactantion-selective electrodes: A promising approach to the study of the aggregation of ionic surfactants in solution

“…This kind of electrode has been extensively used by Wyn-Jones et al 48,[54][55][56][57]138,[140][141][142][143][144][145][146][147][148] and by the groups of Shirahama and Hayakawa. 49,[149][150][151][152][153][154] From Table 1, one can see that the polymers are mainly focused on PVP, PEO, PVA, HEUR, CD, MC, NaPA, PAMPS, Chitosan, and triblock-polymers such as Pluronic F68 (EO 76 PO 29 EO 76 ) and F127 (EO 97 PO 69 EO 97 ). [53][54][55][56]74 Anionic surfactants include sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), etc.…”

Study on Rheologic Behavior and Molecular Configuration in the Mixed Systems of Polyacrylamide and Surfactants

“…Particularly, the three-stage model [17] suggested by Biggs gained wide acceptance, in which the viscosity changes and the molecular configuration of the mixed systems can be divided into three stages with the increase of surfactant concentration. Many reports [18][19][20][21][22] showed that the interactions between HMP and surfactants might be also controlled by such factors as pH of the solutions, salts and hydrogen bounds between them, in addition to the properties of HMP and surfactants. The information of all these influences can be reflected from the conformations of the mixed system.…”