Abstract:This critical review covers the recent progress in the research of mesogen-jacketed liquid crystalline polymers (MJLCPs), special side-on side-chain liquid crystalline polymers with very short spacers or without spacers. MJLCPs can self-organize into supramolecular columnar phases with the polymer chains aligned parallel to one another or smectic phases with the backbones embedded in the smectic layers. The semi-rigid rod-like MJLCP with a tunable rod shape in both length and diameter provides an excellent bui… Show more
“…After heating to higher temperatures, taking at 150 C as an example, two peaks develop in the low-angle region, and the broad halo in the wide-angle region slightly shifts to lower angles due to thermal expansion. The corresponding d-spacing values of the two peaks in the low-angle region are 1.83 and 1.65 nm, which can be assigned as (100) and (010), diffractions of a rectangular structure with a = 1.83 nm, b = 1.65 nm, and = 90, and this rectangular structure possesses only a 2D positional order, exhibiting features of a columnar phase, similar to many MJLCPs [54,55] . Because of the possible rotation of the ester linkage, the whole side-chain length cannot be precisely estimated.…”
Section: Phase Structure Identification Of the Polymersmentioning
A series of side chain liquid crystalline polymers (SCLCPs) containing triphenylene (Tp) units in the side chains, denoted as PMTS (without spacer) and PMTnS (n = 2, 3, 4, 6, which is the number of the methylene units between the main chain and Tp moieties in the side chains), with different lengths of spacers were synthesized through conventional free radical polymerization. The chemical structures of the monomers were confirmed by 1 H/ 13 C-NMR, and the phase behaviors were examined by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide-angle X-ray diffraction (1D and 2D WAXD). The molecular characterization of the polymers was performed with 1 H-NMR, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D and 2D WAXD. The results showed that the length of spacer has significant effects on the LC phase behavior of polymers. For PMTS and PMT2S, they displayed the columnar phase developed by the Tp moieties and the main chain as a whole due to the strong coupling effect of the Tp moieties and the main chain. For the PMT3S, PMT4S and PMT6S, they formed the symmetry hexagonal columnar (Φ H ) phase owing to the decoupling effect. All of these indicated that the "decoupling effect" or "coupling effect" depended on the length of spacers, leading to the different LC phase formation mechanism.
“…After heating to higher temperatures, taking at 150 C as an example, two peaks develop in the low-angle region, and the broad halo in the wide-angle region slightly shifts to lower angles due to thermal expansion. The corresponding d-spacing values of the two peaks in the low-angle region are 1.83 and 1.65 nm, which can be assigned as (100) and (010), diffractions of a rectangular structure with a = 1.83 nm, b = 1.65 nm, and = 90, and this rectangular structure possesses only a 2D positional order, exhibiting features of a columnar phase, similar to many MJLCPs [54,55] . Because of the possible rotation of the ester linkage, the whole side-chain length cannot be precisely estimated.…”
Section: Phase Structure Identification Of the Polymersmentioning
A series of side chain liquid crystalline polymers (SCLCPs) containing triphenylene (Tp) units in the side chains, denoted as PMTS (without spacer) and PMTnS (n = 2, 3, 4, 6, which is the number of the methylene units between the main chain and Tp moieties in the side chains), with different lengths of spacers were synthesized through conventional free radical polymerization. The chemical structures of the monomers were confirmed by 1 H/ 13 C-NMR, and the phase behaviors were examined by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide-angle X-ray diffraction (1D and 2D WAXD). The molecular characterization of the polymers was performed with 1 H-NMR, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D and 2D WAXD. The results showed that the length of spacer has significant effects on the LC phase behavior of polymers. For PMTS and PMT2S, they displayed the columnar phase developed by the Tp moieties and the main chain as a whole due to the strong coupling effect of the Tp moieties and the main chain. For the PMT3S, PMT4S and PMT6S, they formed the symmetry hexagonal columnar (Φ H ) phase owing to the decoupling effect. All of these indicated that the "decoupling effect" or "coupling effect" depended on the length of spacers, leading to the different LC phase formation mechanism.
“…With the development of the structural library of MJLCPs, many efforts have been expended and targeted on the molecular engineering of the MJLCP main chains. The first reported series of MJLCPs are based on polyacrylates and poly (meth) acrylates (Hessel andFinkelmann 1985, 1986;Chen et al 2010). When compared to polyacrylates, the poly (meth) acrylate backbone tends to depress the LC phase formation, indicating the influence of the polymer backbone on liquid crystallinity.…”
Matters comprise of molecules that exist in three different phases-solids, liquids and gases depending on their arrangement. The arrangement of molecules in a crystalline solid leads to long-range positional and orientational orders. In isotropic liquid, on the other hand, the molecules are arranged randomly and possess no order and flow freely. However, it was observed that a certain class of molecules organise in a different manner in order to exhibit a new phase, popularly known as liquid crystalline phase. Molecules in liquid crystalline phase self-organize, leading to positional/orientation order. Macroscopically, the liquid crystalline phase exhibits flow and appears like an opaque fluid.
“…[1][2][3][4] In these LC structures, the combination of ordered packing of rod blocks and separation of immiscible rod/coil blocks determines the structural characteristics. [5][6][7] Generally, the LC microstructures possess only one structure period at the nanoscale, for example, the smectic structure formed by rod-coil diblock copolymers.…”
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