Ionomer‐surfactant self‐assembly in low‐polarity solvents

Abstract

A systematic study of complexation reactions of sulfonated polystyrene ionomers containing up to 5 molar percent of polar chain units with various oil-soluble surfactants is carried out in low-polarity organic solvents. Dipole-dipole attractions of the components lead to the formation of complexes characterized by limiting compositions and an unusual polymer-colloidal morphology of joint clusters and/or micelles. The limiting compositions (cp) for the complexes formed between ionomers and surfactant of the same charge (bis(2-ethylhexy1)suIfosuccinate sodium salt), or nonionic surfactants (primarily aliphatic amines) are equal to 15-30 surfactant molecules per one ionomer salt/acid group on average, with cp depending on the hydrophilic-lypophilic balance of the components, the initial aggregation state of surfactant and the nature of low-polarity solvent. lonomersurfactant complexation is accompanied by disruption of self-contacts of ionomer salt/acid groups, leading to "unfastening" and expansion of the ionomer coils in dilute solution. The "driving force" of the ionomersurfactant complexation and the structure of the resultant complexes are discussed.

Complexes of oil-soluble amphiphilic copolymers and low-molecular mass surfactants

“…Velocity sedimentation (ultracentrifugation) and vapor pressure osmometry techniques were used to study complexation between ionomers and AOT surfactant. A detailed discussion of sedimentograms for ionomer-AOT mixtures is given elsewhere [5,6]. The data on interaction of ionomers and AOT reversed micelles containing water will be discussed below.…”

“…pressure osmometry techniques. We will not discuss here the procedures of such estimations, since they are described in detail elsewhere [5,6]. Table 2 shows the data on the limiting compositions of complexes for ionomers and AOT surfactant in slightly aggregated state and reversed micelles containing water.…”

“…1. Distilled water and purified lowpolarity solvents were used in all studies [4]. We used 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSNa), obtained from Eastman Kodak, as water-soluble probe solubilized into AOT-H 2 O reversed micelles to detect those micelles in velocity sedimentation experiments.…”

“…Velocity sedimentation experiments were performed using a Beckman-E analytical ultracentrifuge at =48 000 rpm and T= 25°C. Vapor pressure osmometry experiments were carried out at various temperatures using mostly a Wescan-233 vapor pressure osmometer as is described in [5,6].…”

Synthesis and Properties of Stereoregular Cyclic Polysilanols: cis-[PhSi(O)OH]4, cis-[PhSi(O)OH]6, and Tris-cis-tris-trans-[PhSi(O)OH]12

“…Molecular weights were determined by vapor pressure osmometry (VPO) on Wescon (solvent: acetone, 25 °C) according to the method described previously …”