Preparation of a Ferroelectric Liquid Crystal Electrolyte Solution

A ferroelectric liquid crystal was synthesised. We attempted electrochemical polymerisation in ferroelectric liquid crystal.


INTRODUCTION
Polymerisation is usually carried out in liquid solvents. Because the molecules do not have a position and an orientation order in liquid state, the polymer being synthesized in the isotropic solvent does not show a certain order. Liquid crystals (LC) have fluidity, which can be used as a solvent in the polymerisation reaction.
The polymers obtained in LC have an ordered structure because of occurrences of transcription of ordered structure from LC. We achieved synthesis of conjugated polymers having molecular order of chiral nematic liquid crystal [1]. We attempt electrochemical polymerisation in a chirals mectic C (SmC*) as a ferroelectric LC. SmC* can provide chiral environment with highly ordered helical structure. In the present study, preparation of SmC*-LC for chiral electrolyte solution is carried out.

3. Polarising optical microscopy observation
The results of polarising optical microscopy (POM) observation are shown in Figure  3-5. Figure 3 displays typical fan-shaped structure at 94 °C on cooling, indicating SmA* phase.  Figure 4 shows broken fan-shape structure in 55 °C on cooling, indicating SmC* phase. The wrinkle appeared at 55 °C, and the texture was changed to fan-shaped texture at 38.9 °C on cooling, indicating LC-1 shows SmC A * phase.

ILCPA Volume 46
Phase sequence of LC-1 was determined by results from the DSC and observation of POM, as follows.

4. Polymerisation in SmC*
We prepared electrolyte solution consisting of LC-1, n-tetrabutyl ammonium perchlorate (TBAP), and bithiophene. The mixture was injected to indum-tin-oxide (ITO) coated glass sandwich cell with thin Teflon spacer. Electrochemical polymerization was then carried out by applying voltage of 20 V (Scheme 6). We observed optical textures of the electrolyte solution during the electrochemical polymerisation by using POM. The results are shown in Figure 6. Color of the polymerisation cell changed periodically yellow-red-yellow in every one minute (Figure 6 A-C).

CONCLUSIONS
A ferroelectric liquid crystal was synthsised. Subsequently, electrochemical polymerisation was carried out in the liquid crystal. Orientation of molecules did not change in the polymerisation cell during the electrochemical polymerisation. The ferroelectric liquid crystals form spontaneous polarisation with gold stone mode [2]. In the future work, electrical interaction of the monomer and the ferroelectric LC at the anode interface needs to be examined.