Influence of Layered Silicates on the Phase-Separated Morphology of PS−PVME Blends

• Published in: Macromolecules 2003-09, Vol.36 (19), p.7256-7267
• Main Authors: Yurekli, Koray, Karim, Alamgir, Amis, Eric J, Krishnamoorti, Ramanan
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma020755l

The influence of the disk diameter of nanometer thick anisotropic layered silicates on the phase-separated morphology of a near-critical polystyrene (PS)−poly(vinyl methyl ether) (PVME) blend was examined using atomic force microscopy. Films with comparable amounts of thermodynamically equivalent nanoparticles varying only in lateral disk diameters were examined using a temperature gradient method and showed dramatic differences in late-stage morphology. The blends with small disk diameter (30 nm and 0.5 μm) nanoparticles exhibit a pinning of domain sizes and demonstrate an increase in the number of domains with a higher fraction of near circular structures. On the other hand, for layered silicates with large disk diameters (10 μm), the nanoparticles do not affect the morphology of the phase-separated structure and only accelerate the phase separation kinetics. The extent of domain pinning increases with increasing silicate content and results in smaller domains at higher concentrations of silicate.