Synthesis and Self-Assembly of Rod-Coil Molecules with n-Shaped Rod Building Block

The rod-coil molecules with n-shaped rod building block, consisting of an anthracene unit and two biphenyl groups linked together with acetylenyl bonds at the 1,8-position of anthracene as a rigid rod segment, and the alkyl or alkyloxy chains with various length (i.e., methoxy- (1), octyl- (2), hexadecyl- (3)) at the 10-position of anthracene and poly(ethylene oxide) with the number of repeating units of 7 connected with biphenyl as coil segments were synthesized. The molecular structures were characterized by H-1 NMR and MALDI-TOF mass spectroscopy. The self-assembling behavior of new type of molecules 1-3 was investigated by means of DSC, POM, and SAXS at the bulk state. These molecules with a n-shaped rod building block segment self-assemble into supramolecular structures through the combination of pi-pi stacking of rigid rod building blocks and micro-phase separation of the rod and coil blocks. SAXS studies reveal that molecules 1 and 2 show hexagonal columnar and rectangular columnar structures in the liquid crystalline phase, respectively; meanwhile, molecules 1-3 self-organize into lamellar structures in the crystalline state. In addition, self-assembling studies of molecules 1-3 by DLS and TEM indicated that these molecules self-assemble into elongated nanofibers in aqueous medium. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48:1415-1422, 2010