Smectic Phases of MJLCPs
The MJLCP with semifluorinated tails in the side group synthesized by Ober et al.
exhibits a smectic C (SmC) phase (Gopalan et al. 2002). The microphase separation
between fluorinated components and hydrocarbons plays an important role in the
formation of the smectic phase.
When more rigid side-chain cores, which usually lead to increased side-chain
rigidity and interactions, are introduced into MJLCPs, smectic phases can develop.
PBPVBP (polymers 6 with n = 4 in Chart 1) shows a smectic A (SmA) phase (Chen
et al. 2007). As shown in Fig. 5a, the 1D WAXD profiles of the polymer display three
strong low-angle diffraction peaks with a scattering vector ratio of 1:2:3, indicating a
smectic structure. The SmA phase is identified from the 2D WAXD pattern (Fig. 5b),
in which the strong diffractions attributed to the layered structures and the amorphous scattering owing to the lateral packing of the MJLCP supramolecular mesogens are perpendicular to each other. Polymer 6 with longer alkoxy tails forms SmC
phases (Chen et al. 2009).
Special Properties of MJLCPs
Chain Rigidity
The rigidity of MJLCPs was proposed when the first MJLCPs were reported (Zhou
et al. 1987, 1989), after which Hardouin et al. performed small-angle neutron
scattering (SANS) studies on side-on SCLCPs (Hardouin et al. 1991, 1992). Their
results confirmed the rigidity of the polymers and the jacketed model.
Fig. 5 1D (a) and 2D (b) WAXD patterns of polymer 6 PBPVBP. (Reprinted and adapted with
permission of the American Chemical Society Chen et al. 2007)
2 Mesogen-Jacketed Liquid Crystalline Polymers: Molecular Design and. . .
35
The MJLCP with semifluorinated tails in the side group synthesized by Ober et al.
exhibits a smectic C (SmC) phase (Gopalan et al. 2002). The microphase separation
between fluorinated components and hydrocarbons plays an important role in the
formation of the smectic phase.
When more rigid side-chain cores, which usually lead to increased side-chain
rigidity and interactions, are introduced into MJLCPs, smectic phases can develop.
PBPVBP (polymers 6 with n = 4 in Chart 1) shows a smectic A (SmA) phase (Chen
et al. 2007). As shown in Fig. 5a, the 1D WAXD profiles of the polymer display three
strong low-angle diffraction peaks with a scattering vector ratio of 1:2:3, indicating a
smectic structure. The SmA phase is identified from the 2D WAXD pattern (Fig. 5b),
in which the strong diffractions attributed to the layered structures and the amorphous scattering owing to the lateral packing of the MJLCP supramolecular mesogens are perpendicular to each other. Polymer 6 with longer alkoxy tails forms SmC
phases (Chen et al. 2009).
Special Properties of MJLCPs
Chain Rigidity
The rigidity of MJLCPs was proposed when the first MJLCPs were reported (Zhou
et al. 1987, 1989), after which Hardouin et al. performed small-angle neutron
scattering (SANS) studies on side-on SCLCPs (Hardouin et al. 1991, 1992). Their
results confirmed the rigidity of the polymers and the jacketed model.
Fig. 5 1D (a) and 2D (b) WAXD patterns of polymer 6 PBPVBP. (Reprinted and adapted with
permission of the American Chemical Society Chen et al. 2007)
2 Mesogen-Jacketed Liquid Crystalline Polymers: Molecular Design and. . .
35