Toroid morphology by ABC-type amphiphilic rod-coil molecules at the air-water interface.
The interfacial and aggregation behavior of the ABC-type amphiphilic molecules with semirigid dumbbell-shaped core and variable length of hydrophobic branched tails (R=(CH2)nCH3 with n=5 (1), 9 (2), 13 (3)) were investigated. At low surface pressure, smooth, uniform monolayers were formed at the air-water interface by molecules 1 and 2, whereas for molecule 3 unique 2D toroid aggregates have been formed. These aggregates were relatively stable within a range of surface pressure and spreading solution concentration. Upon compression, the 2D toroid aggregates collapsed into large, round 3D aggregates. Finally, the choice of spreading solvent has a great influence on aggregation formation into 2D or 3D micelles as a result of the variable balance of the hydrophobic interactions of branched tails and the pi-pi stacking interaction between aromatic segments.
Center for Supramolecular Nano-Assembly, Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Libin
L
Liu
Jung-Keun
JK
Kim
Ray
R
Gunawidjaja
Vladimir V
VV
Tsukruk
Myongsoo
M
Lee