A charge transfer complex nematic liquid crystalline gel with high electrical conductivity

Abstract

We describe the rheological, dielectric and elastic properties of a nematic liquid crystal gel created using an anthrylidene derivative of arjunolic acid, a chiral triterpenoid, obtained from the extracts of the wood of Terminalia arjuna. In this novel gel, having the electron-donor and acceptor components as minority constituents, the gelation and strengthening of charge-transfer complex (CTC) formation are seen to be occurring concomitantly. In addition to being mechanically strong with a large storage modulus, the gel with the maximized CTC exhibits Frank bend elastic constant values that approach nanonewton levels. The highlight of the study is the observation of 4–5 orders of magnitude increase in electrical conductivity for this gel, a value that is higher than even in the CT complexes of 2-d ordered columnar structures. A further important advantage of the present system over the columnar complex is that the high conductivity is seen for ac probing also, and owing to the nematic nature can be switched between its anisotropic limits. Some of these features are ascribed to a specific molecular packing architecture, which reduces the trapping of the charge carriers.

Self‐assembly of Renewable Nano‐sized Triterpenoids

“…Functionally rich naturally occurring triterpenoids with several hydroxyl and carboxyl groups offers innumerable opportunities for the generation of triterpenoid derivatives depending upon ones design and requirements . Some of the triterpenoids also occur in nature as salts or linked with sugars as in triterpenoid saponins in some plants .…”

“…A nematic liquid crystal gel was generated using the anthrylidene derivative of methyl arjunolate 59 v in the presence of stoichiometric amount of picric acid and ZLI3701‐100 as the nematic liquid crystal (Figure , ) . In this novel gel, the gelator components though present as minor components, provided additional strength to the liquid crystal gel.…”

Incorporation of graphene oxide into C12E4/C12mimBr hybrid lyotropic liquid crystal and its thermo-sensitive properties

“…37, 38 We compared the properties of GO/C 12 E 4 /C 12 mimBr LLC composites between lamellar phase and hexagonal phase and the results are shown in Figure 5. The d-spacing of the lamellar lattice was calculated by d = 2π/q 1 (q 1 was the value of the first peak).…”

“…Rheological measurements can give macro properties of the system in real-time and then reect the change of internal microstructure; thus, it is an important method to investigate LLC materials. 37,38 We compared the properties of GO/C 12 E 4 /C 12 mimBr LLC composites between lamellar phase and hexagonal phase and the results are shown in Fig. 5.…”

Diminished Splay Stiffening in Weak Gels of Calamitic–Bent-Core Nematic Composites

“…The gels composed of the calamitic or the rodlike variety of LCs have been quite well studied, and a number of interesting results have emerged. Notable among the features seen for the gels in comparison with the corresponding nematic sol state are faster electro-optic response, − flexible displays, exceptionally large Frank elastic constant, high electromechanical response, rewritable patterning, bistable nematic states, molecular conductivity, enhanced hole mobility, stabilization of the magnetic nanoparticle dispersion, and high electrical conductivity . Such gels have also been found quite interesting for their viscoelastic behavior exhibiting soft-glass rheological features .…”