Revisiting the Morphology Development of Solvent-Swollen Composite Polymer Particles at Thermodynamic Equilibrium

• Published in: Langmuir Vol. 23; no. 11; pp. 5914 - 5919
• Main Authors: Saito, Naohiko, Kagari, Yoshimi, Okubo, Masayoshi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 22.05.2007
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Dispersed phase; Hydrocarbon; Interface tension; Toluene; Methyl methacrylate polymer; Polymer; Droplet; Free energy; Thermodynamic equilibrium; Composite material; Lauryl sulfate; Drop; Particle; Morphology; Phase separation; Benzenic compound; Styrene polymer; Calculation; Aqueous solution; Thermodynamic properties; Physicochemical properties
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la063653n

Morphology of polystyrene (PS)/poly(methyl methacrylate) (PMMA)/toluene droplets, in which phase separation proceeds, dispersed in SDS aqueous solution was examined. It changed from ex-centered PS-core/PMMA-shell to hemisphere with increasing SDS concentration. At low polymer weight fraction (w p), PS and PMMA phases contained non-negligible amount of PMMA and PS, respectively. The small amount of PS and PMMA in PMMA and PS phases, respectively, affected significantly the interfacial tension between polymer/toluene and aqueous solutions. Interfacial tension between PS and PMMA phases at low w p was measured by the spinning drop method, showing a quite low value (≈10-2 mN/m). Predicted morphology obtained from calculation of minimum total interfacial free energy of the droplets using the interfacial tensions agreed well with the experimental observation.