Amphotropic Liquid Crystals

Ionic Liquid Crystals: Versatile Materials

“…A further distinction can be made between (i) ILCs with cations carrying simple long alkyl chains (which make up the majority of all investigated compounds, mainly because of the ease of synthesis) (Figure a); (ii) ILCs in which the charged moiety (e.g., an imidazolium cation, which is a polarizable rigid group) is incorporated in the rigid part of the mesogen (Figure b); (iii) ILCs with conventional mesogenic groups attached via a flexible spacer to the organic cation (either terminally or laterally; Figure c); and (iv) wedge-shaped ILCs (Figure d). The thermotropic LC properties of compounds of type (a) are mainly due to their strong amphiphilic character, which also explains their lyotropic mesomorphism. , Compounds of type (b) constitute examples of more classically shaped systems, where excluded volume effects play a primary role apart from amphiphilicity. Compounds of type (c) can be considered in a way as nonsymmetric LC dimers (two rigid moieties whose molecular motion is restricted due to their connection via a flexible spacer). − The wedge-shaped type (d) compounds can form cylindrical supramolecular aggregates forming columnar and cubic mesophases (see below).…”

Preparation of amphotropic liquid crystalline poly(alkoxycarbonylphenylene)s

“…cellulose derivatives also show amphotropism 8) . As to synthetic polymers, block copolymers are fundamentally qualified to be amphotropic.…”

“…Exceptionally poly(hexyl isocyanate) was reported to be amphotropic 9,10) . The present communication describes syntheses and properties of ester-substituted poly(p-phenylene)s and poly(m-phenylene)s. We found that these polymers show amphotropism which is of current interest 8) . …”

“…Alternative copolymers of sodium benzenesulfonate with 4-dodecyltoluene also showed a Schlieren texture in DMSO 7) . Amphotropic behavior was widely found for amphiphilic molecules such as detergents and diols, and for natural products such as lipids and cellulose derivatives 8) . However, this behavior was rarely found for synthetic polymers.…”

Thermal Behavior of Dodecylpyridinium-Based Surfactant Salts with Varied Anionic Constituent

“…The benzene ring has been found to be equivalent to 4-5 methylene groups on the alkyl chain. 52 The ring may also stabilize the sulfonate group by resonance, leading to charge density lowering, and hence being simultaneously part of the polar headgroup with delocalized charge, and also a part of the hydrophobic alkyl chain. This could lead to mutual stabilization of cationic and anionic polar headgroups, and in general stabilization of the whole molecule.…”