Copolymer-Layered Silicate Hybrid Surfactants from the Intercalation of Montmorillonite with Amphiphilic Copolymers

• Published in: Langmuir 2003-06, Vol.19 (13), p.5184-5187
• Main Authors: Lin, Jiang-Jen, Hsu, Yen-Chi, Chou, Chih-Cheng
• Format: Article
• Language: English
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la034022l

A novel class of surfactants was prepared from the ionic exchange reaction of sodium montmorillonite (MMT) and a comb-branch shape of maleated polypropylene (MPP) derived copolymers consisting of pendent quaternary ammonium salts, polyoxyalkylene linkers, and a polypropylene (PP) backbone. The hybrid surfactant is composed of a hydrophilic silicate core and a hydrophobic PP corona. In the silicate core, there are approximately 6−10 silicate layers which are intercalated by multiple ammonium salts of the copolymer at d spacing of 19 Å. Surrounding the core, the flexible PP strains contribute to the hydrophobic property in balancing with the hydrophilic silicates to form a water-in-oil (W/O) type cluster structure. When using 2000 g/mol molecular weight poly(oxyethylene)amine, the copolymer (MPP-POE2000) intercalated MMT hybrid was found to be dispersed well in toluene at an average 570−580 nm particle diameter. The aggregated particles exhibited an ability of lowering the toluene/water interfacial tension until 5.0 mN/m at a critical concentration of 0.01 wt %. The aggregated particle size is indifferent to the temperature change in the range 25−75 °C, implying the unusual thermal stability of the MMT-template hybrid surfactants and possibly the presence of a single-molecular surfactant micelle with the MMT primary particle as the central hydrophilic core.