Modulation of Phase Separation Between Spherical and Rodlike Molecules Using Geometric Surfactancy

• Published in: Langmuir 2010-08, Vol.26 (15), p.12877-12881
• Main Authors: Zeng, Lichang, Blanton, Thomas N, Chen, Shaw H
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Cross-disciplinary physics: materials science; rheology; Emulsions. Microemulsions. Foams; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General and physical chemistry; Materials science; Materials: Nano-and Mesostructured Materials, Polymers, Gels, Liquid Crystals, Composites; Physics; Specific materials
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la1014797

A Dyad consisting of C60 linked to a π-conjugated oligomer by a propylene spacer was synthesized to explore its ability to modulate phase separation between OFTB and PCBM using differential scanning calorimetry, hot-stage polarizing optical microscopy, X-ray diffraction, and atomic force microscopy techniques. Upon thermal annealing at 10 °C above its T g for 12−48 h, the 1:1 blend of OFTB and PCBM resulted in a eutectic mixture. Thermal annealing of a OFTB:Dyad:PCBM film with a 9:2:9 mass ratio at 10 °C above its T g for 12 h resulted in an amorphous film. Its AFM phase image indicated phase separation into two interspersed 30 nm amorphous domains at approximately equal fractions. Geometric surfactancy is inferred from the formation of microemulsions in analogy to widely reported traditional oil−surfactant−water systems and ternary polymer blends. In contrast, thermal annealing of a 7:6:7 film under a similar condition resulted in an amorphous film with compositional uniformity.