Self-assembly of ABC coil-rod-coil triblock molecules with perforated lamellar mesophases

The synthesis and characterization of ABC coil-rod-coil triblock (monomer) and ABCBA coil-rod-coil-rod-coil triblock dimer (dimer) molecules of docosyl 4-[4-[methyloxypoly(ethyleneoxy)ethyloxy]-4-biphenylcarboxyloxy]-4-biphenyl carboxylate with poly(ethylene oxide) (PEO) coil are described. The self-assembling behavior of triblock molecules is characterized by a combination of techniques consisting of differential scanning calorimetry (DSC), thermal polarized optical microscopy (POM), and X-ray diffraction (XRD) measurement. Monomer and dimer self-assemble into three lamellar crystalline phases (k(1), k(2), and k(3)) and 3D-hexagonally perforated lamellar (HPL) and 2D-hexagonal columnar (col) liquid crystalline phases as temperature increases. In addition to the phases exhibited by monomer, dimer shows 3D-tetragonally perforated lamellar (TPL) and spherical micellar (M) liquid crystalline phases. These results demonstrate that simple dimerization of coil-rod-coil molecule by connecting PEO block induces 3D-tetragonally perforated lamellar and spherical micellar mesophases. (c) 2006 Elsevier Ltd. All rights reserved.