Polymerization of Styrene in Ternary Microemulsion Using Cationic Gemini Surfactants

Abstract

The use of cationic dimeric (“gemini”) surfactants in the oil in water (o/w) microemulsion polymerization of styrene is reported. Gemini surfactants of the alkanediyl-α,ω-bis(dimethylalkylammonium bromide) type (m-s-m) with m being 12 and s being 2, 4, 6, 8, 10, and 12 were used. The phase behavior of the microemulsion is decisively influenced by the spacer length s. All surfactants form single-phase o/w microemulsions with styrene in a temperature range from 25 to 60 °C. For s being 2, only very small stable microemulsion regions were observed, while for s being 4, 6, and 8, the clear and stable regions were gradually increased. The shape of the single-phase regions was very similar to that of the analogous single tail surfactant dodecyltrimethylammonium bromide. For s being 10, the microemulsion region was distinctly extended, while for s being 12, it was decreased again at low temperature, but even more increased at high temperature. Polymerization of the monomeric microemulsions led to spherical latex particles, whose size range could be easily controlled by the monomer/surfactant ratio. A significant dependence of the particle size on the surfactant spacer length was observed. At 25 °C, the particle size was maximum for s being 10, at 60 °C the particle size increased with s. Therefore, the particle size was directly correlated with the size of the single-phase microemulsion region. The molecular weight was maximum at medium spacer length. The experimental results are discussed by taking into account hydrophobic and electrostatic effects and the respective microdroplet structure resulting from the varying interfacial spontaneous curvature due to the different surfactant shapes.

Dimeric (Gemini) Surfactants: Effect of the Spacer Group on the Association Behavior in Aqueous Solution

“…The solubilizing capacity increased progressively by a factor of about 5 as s increased from 2 to 12 and temperature had a strong effect (92). This effect of the spacer length is opposite to that reported by Dam et al (90) for the solubilization of toluene and n-hexane also in 12-s-12 micellar solutions.…”

“…The partial phase diagrams of the ternary systems water/12-EO z -12/styrene (15) and water/12-s-12/styrene have been reported (92). The studies focused on the effect of the spacer length and nature on the extent of the one-phase region (microemulsion range) in the systems.…”

“…The studies focused on the effect of the spacer length and nature on the extent of the one-phase region (microemulsion range) in the systems. Figure 16 shows that the extent of the microemulsion range is a maximum at s = 10 for the water/12-s-12/styrene system (92) and that it strongly depends on temperature. The one-phase region for the water/12-EO z -12/styrene systems has a maximum extension at n T = 5, i.e., with the 12-EO z -12 surfactant, and depends only little on temperature (15).…”

A theoretical investigation of the influence of the second critical micelle concentration on the solubilization capacity of surfactant micelles

“…Comprehensive experimental systematic studies of the solubilization of long-chain hydrophobic components by gemini surfactant micelles are, unfortunately, still missing and experimental evidence of the role of spacer group length is, to our knowledge, not yet available. [43][44][45][46][47] …”

Urea-based gemini surfactants: Synthesis, aggregation behaviour and biological activity

“…Gemini surfactants can also serve as structural units in the formulation of cationic liposomes [23]. As for industrial applications, gemini surfactants show inhibitive effect on iron corrosion [24], act as efficient agents in oil recovery [25], styrene polymerisation [26,27], dying of textiles [28,29]. They appeared to be good stabilisers of polymer latex particles [30], separation agents in capillary chromatography [31], gelators of organic solvents [32], and reactants in the synthesis of silica mesophases [33].…”