Design of Viologen-Based Liquid Crystals Exhibiting Bicontinuous Cubic Phases and Their Redox-Active Behavior.

Tsubasa Kobayashi,Takahiro Ichikawa,Takahiro Ichikawa

doi:10.3390/ma10111243

Tsubasa Kobayashi, Takahiro Ichikawa + Show 1 more

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https://doi.org/10.3390/ma10111243

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Abstract

We have succeeded in developing viologen-based liquid-crystalline materials forming bicontinuous cubic phases. They are composed of amphiphilic zwitterions with a viologen ionic-head-group and sulfonyl-imide-type acids. In the bicontinuous cubic liquid-crystalline assemblies, the ionic-head groups of the amphiphiles align along a gyroid minimal surface, forming a 3D continuous viologen layer. The ionic state of the viologen-moieties can be tuned from a dication state (V2+) to a radical mono cation state (V1+•) by UV irradiation and/or electric field. This redox reaction proceeds in bulk, accompanying the change of their color from colorless to purple. Interestingly, they preserve the 3D molecular assembled structures beyond the redox reaction, which has been confirmed by polarizing optical microscopy and X-ray diffraction measurements.

Highlights

Viologen is a class of ionic compounds with bipyridinium dication structures (V2+ )
To realize design realize the design of viologen-based amphiphilic molecules exhibiting Cubbi LC phases, we the employed of molecules exhibiting
Based on onthe theabove above results, envision if a certain physicochemical of the derivative liquid crystals can be largely changed by reduction, this change can be exploited induce viologen derivative liquid crystals can be largely changed by reduction, this change can be to exploited switchable a potentialAs physicochemical property, we focused on the hydrophilicity of the to induce functions

Summary

Introduction

Viologen is a class of ionic compounds with bipyridinium dication structures (V2+ ) It is a representative redox-active molecule showing specific chemical response to photo- and electro- stimuli. Murray reported that the successive alignment of viologen groups along a polymer backbone enables a fast, self-electron transfer reaction. These materials are applicable for redox-flow batteries [9]. Another useful strategy for aligning viologen groups into an ordered manner is to endow them with liquid crystallinity through suitable molecular design [10,11,12,13,14,15,16,17]. The polymerization of the pyrole moiety yields LC polymers forming smectic (Sm) phases, which act as both 2D ions

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