Conductivity studies on the effect of a nematic liquid crystal on polyvinyl alcohol-based electrolytes

Recently, a few studies have shown that the introduction of liquid crystals (LCs) in polymer electrolytes would lead to an increase in the chain mobility and the ionic conductivity. It is believed that this enhancement of the polymer electrolyte performance is greatly influenced by the order parameter of the liquid crystal in this system. In this study, a deuterated 4-pentyl-4'-cyanobiphenyl (5CB-d2) nematic liquid crystal-doped polyvinyl alcohol (PVA) polymer electrolyte were prepared. The orientational order of the nematic liquid crystal is then investigated via the quadrupolar splittings of the deuterium Nuclear Magnetic Resonance (NMR) spectra. The quadrapolar splitting, which is directly related to the orientational order of the liquid crystal director, was measured and compared between the embedded 5CB-d2 in the PVA electrolyte to that of the pure 5CB-d2. The conductivity of a 5CB-d2 embedded in PVA reached up to 3.28×10-1 S/cm compare to that of without 5CB-d2 which is only 2.89×10-1S/cm. The presence of 5CB-d2 in the PVA polymer electrolyte improved the electrical conductivity of the mixture through an improved charge transfer mechanism, which improves its electrical properties, a criterion useful for a device that needs high conductivity. © (2014) Trans Tech Publications, Switzerland

Polymer electrolyte liquid crystal system for improved optical and electrical properties

Polymer electrolytes are electrolytes that consist of polymer/salt complex and contain free ions which render them electrically conductive. They are used extensively in applications such as batteries, capacitors, and photovoltaic cells. In this study, a series of 4-cyano-4′-pentylbiphenyl (5CB) nematic liquid crystal-doped polyvinyl alcohol (PVA) polymer electrolytes were prepared and the effects of the concentration of the doped 5CB on the properties of the electrolytes were characterized by alternating current (AC) impedance spectroscopy. The increase in conductivity which was achieved through the doping of 5CB suggests that the embedded liquid crystal (LC) molecules increased the ordering strength in the electrolyte, which provides a better pathway to transfer generated charges inside the polymer electrolyte. Characterization of the polymer electrolyte liquid crystal system (PeLCs) by electrochemical and spectroscopic techniques reveals the influence of LC in the PeLC optical and electrochemical band gaps

Polymer electrolyte liquid crystal mixtures as phase-dependent thermoelectric materials

Organic thermoelectric materials have gained a trajectory in recent years given its advantages of processability, low cost and flexibility. In this paper, polymer electrolyte liquid crystal (PELC) mixtures composed of polyvinyl alcohol, potassium iodide, and 4-Cyano-4'-pentylbiphenyl (5CB) liquid crystal are fabricated, the 5CB acts as a ‘temperature switch’, i.e., a strong correlation between the thermoelectric properties and the transition from Ne-Iso transition of the 5CB, is observed. The electrical conductivity and Seebeck coefficient of the PELC mixtures both decrease above the Ne-Iso transition temperature. This thermoelectric behavior is discussed in terms of the carrier concentration, carrier mobility, and order-disorder transition