Probing the Texture of the Calamitic Liquid Crystalline Dimer of 4-(4-Pentenyloxy)benzoic Acid

Abstract

The liquid crystalline dimer of 4-(4-pentenyloxy)benzoic acid, a member of the n-alkoxybenzoic acid homologous series, was synthesized using potassium carbonate supported on alumina as catalyst. The acid dimer complex exhibited three mesophases; identified as nematic, smectic X1 and smectic X2. Phase transition temperatures and the corresponding enthalpies were recorded using differential scanning calorimetry upon both heating and cooling. The mesophases were identified by detailed texture observations by variable temperature polarized light microscopy. The nematic phase was distinguished by a fluid Schlieren texture and defect points (four and two brushes) while the smectic phases were distinguished by rigid marble and mosaic textures, respectively.

Poly(l-Lactide) Liquid Crystals with Tailor-Made Properties Toward a Specific Nematic Mesophase Texture

“…Ultimately, all order is lost, creating an isotropic liquid. Some compounds pass from the crystalline to the nematic phase, omitting smectic phases. − LCs are formed either by heating (thermotropic LCs) or in the presence of solvents (lyotropic LCs). , Depending on the spatial orientational and positional order of the molecules, thermotropic LCs can be divided into nematic, chiral nematic (cholesteric), and smectic. The N mesophase, one of the most common and important mesophases in applications, is characterized by a high degree of long-range orientational order, but no translational order, making it the least ordered mesophase of the LCs.…”

Liquid crystalline material exhibiting multiple phase transitions: morphologic properties and optical transmission

“…This texture is a modification of a mosaic texture. Such texture type has been observed by various scientists for the N mesophase in different liquid crystals [32][33][34][35]. This texture consists of various uniform regions.…”

“…As seen in Fig. 3(c), the texture of SmC consists of broken polygonal and [33,35,36]. Such type of the texture was presented in [33,34,36,38,39], is characteristic of the C 2h symmetry and corresponds to the SmC mesophase.…”

“…Thus, for the abovementioned phase transitions thermal hysteresis takes place. Availability of thermal hysteresis and T* and T** temperatures at the phase transitions in liquid crystals was theoretically predicted in [11,14,38,[40][41][42][43][44][45][46] and was experimentally observed in [47][48][49][50][51][52][53][54][55][56].…”

Optimized molecular structures of guest–host system for highly efficient coatable polarizer

“…Disclination, which is a line singularity in the overall molecular orientation, is caused by discontinuities within the uniform alignment and provides various structures based on the liquid crystal phase [29][30]. In nematic liquid crystals, disclinations are observed as droplets-textures, thread-textures, or schlieren-textures in the boundary between an isotropic phase and a nematic phase [31][32].…”