are named as mesogens. Mesogens are small organic molecules capable to arrange
concisely in different types of orders or organizations. However, all these mesogens
do not participate in organization or ordering and hence generating an astonishing
material having a combination of both solid and a liquid. For example, gelatin shows
mesophasic nature. The functional behavior of a liquid crystal lies in the organization or order of the mesogens. Since, liquid crystals remain in two states, in a liquid
state, the mesogens become arbitrarily oriented without any directionality and form
an isotropic fluid. Again, in the solid state, the same mesogenic molecules are in a
highly ordered state with no translational degree of freedom. For liquid crystal materials, the difference lies in the sense that the non-symmetrical mesogen molecules are
self-aligned in a particular axis called the director (Fig. 2) (Ermakov et al. 2015). This
positional arrangement is the most critical for the formation of the nematic and smectic
structures as well as solid phases. A nematic liquid crystal molecule retains their
directional orientation; however, it contains some sort of freedom of movement within
the liquid crystals as depicted in Fig. 2a (Kumar 2001). In the smectic phase, the liquid
crystals are arranged in such a way that their principal axis is oriented parallel to the
center of mass of the material in one of the planes, thus exhibiting both positional
and directional order in these molecules, as represented in Fig. 2b and c (Ermakov
et al. 2015). Hence, all the properties of interest of liquid crystals such as optical,
magnetic, and electrical are direction oriented or anisotropic.
Liquid Crystalline Polymers: Specialties
Later on, the researchers have observed that liquid crystals may also produce
polymeric molecules consisting of repeating monomer units, which are connected
to form long-chain molecules. The primary units of the main chain are connected to
each other through a flexible linker of varying chain lengths. These polymeric chains
Fig. 2 Orientational order of mesogens in liquid crystal molecules: (a) nematic, (b) smectic A, and
(c) smectic C
4
S. Banerjee and K. K. Kar
concisely in different types of orders or organizations. However, all these mesogens
do not participate in organization or ordering and hence generating an astonishing
material having a combination of both solid and a liquid. For example, gelatin shows
mesophasic nature. The functional behavior of a liquid crystal lies in the organization or order of the mesogens. Since, liquid crystals remain in two states, in a liquid
state, the mesogens become arbitrarily oriented without any directionality and form
an isotropic fluid. Again, in the solid state, the same mesogenic molecules are in a
highly ordered state with no translational degree of freedom. For liquid crystal materials, the difference lies in the sense that the non-symmetrical mesogen molecules are
self-aligned in a particular axis called the director (Fig. 2) (Ermakov et al. 2015). This
positional arrangement is the most critical for the formation of the nematic and smectic
structures as well as solid phases. A nematic liquid crystal molecule retains their
directional orientation; however, it contains some sort of freedom of movement within
the liquid crystals as depicted in Fig. 2a (Kumar 2001). In the smectic phase, the liquid
crystals are arranged in such a way that their principal axis is oriented parallel to the
center of mass of the material in one of the planes, thus exhibiting both positional
and directional order in these molecules, as represented in Fig. 2b and c (Ermakov
et al. 2015). Hence, all the properties of interest of liquid crystals such as optical,
magnetic, and electrical are direction oriented or anisotropic.
Liquid Crystalline Polymers: Specialties
Later on, the researchers have observed that liquid crystals may also produce
polymeric molecules consisting of repeating monomer units, which are connected
to form long-chain molecules. The primary units of the main chain are connected to
each other through a flexible linker of varying chain lengths. These polymeric chains
Fig. 2 Orientational order of mesogens in liquid crystal molecules: (a) nematic, (b) smectic A, and
(c) smectic C
4
S. Banerjee and K. K. Kar