Biomedical Engineering Reference
In-Depth Information
9
Ionic Discotic Liquid Crystals: Recent
Advances and Applications
Santanu Kumar Pal*
,1
and Sandeep Kumar*
,2
1
Department of Chemical Sciences, Indian Institute of Science Education
and Research, Mohali, India
2
Sot Condensed Matter Group, Raman Research Institute, Bangalore, India
Abstract
Ionic liquids are currently attracting considerable attention as environmentally
benign (green) solvents for various chemical reactions due to their interesting
properties, such as high thermal stability, non-l ammability, very low vapor pres-
sure and reusability. h ey have great potential not only as ordered reaction media
exhibiting high ionic conductivities, but also as functional materials for electro-
chemical devices, reaction solvents, catalysis and so on. However, in almost all
cases, they have been used as functional isotropic liquids. If anisotropic structures
are induced into ionic liquids their properties could be enhanced, ranging from
molecular to macroscopic scale. In particular, introducing columnar structures
formed by discotic liquid crystals (DLCs) is a promising approach to the forma-
tion of self-organized mono-domain in macroscopic scale that play a key role
for the enhancement of the properties. Such hybrid materials (ionic DLCs) not
only exhibit l uid ordered states but also function as anisotropic organic semicon-
ductors that ei ciently conduct ions. In all these cases, control of intermolecular
interaction and formation of phase-segregated structures are key in the design
and development of these materials. Whereas, intermolecular interactions, such
as hydrogen bonding, ionic interactions, charge-transfer interactions, ion-dipole
interactions and π-π interactions can be used for the construction of functional
and ordered supramolecular structures, molecular mixtures consisting of partially
immiscible components and block molecules having immiscible parts can form
phase-segregated morphology from micro- to nanometer scale that induce novel
function into these systems.
