Highlights• Lecithin-formed LC structure in water solution • Preparation of conducting polymer thin films on ITO glass • Lecithin LC structure transcribed to polymer thin films • Island pattern observed in polymer thin films by the SEM.Abstract: Lecithin is a biological material that exhibits lyotropic liquid crystal form at certain concentrations in water. Specifically, lecithin forms lamellar structures like a smectic phase layers. We describe electro-oxidative preparation of polymers such as polyaniline (PANI), poly(ethylenedioxythiophene) (PEDOT), and polypyrrole (PPy) in a lecithin liquid crystal matrix. Cross-shaped images (Maltese crosses) derived from lamellar structures were observed for the resultant polymer film with a polarizing optical microscopy under crossed nicol condition. Lecithin lamellar structure in the water was transcribed to the resultant polymers during the electropolymerization. This research demonstrates transcription of a liquid crystal aggregation form of biomaterials onto synthetic polymers through electrochemical process.
Polyaniline (PANI) is synthesized in the presence of montmorillonite (Mt). Mt has small spaces between its layers. This interlayer spacing functions as a reaction field for the production of PANI with an organized structure. Mt/PANI composites thus synthesized were characterized by the IR and the UV-Vis optical absorption spectroscopy measurements. Scanning electron microscopy observation showed that the PANI is covered by the flake structure of the Mt. A cylindrical structure was also observed in the sample. X-ray diffraction analysis indicated that the composite of the PANI and the Mt had an ordered structure, suggesting that the macroscopic structure of the natural clays can provide a unique reaction field for polymerization reactions.
Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the promising conjugated polymeric materials for organic devices such as organic solar cell or organic electroluminescence display. Hydroxypropyl cellulose (HPC) is a product of chemical-modified cellulose. HPC shows liquid crystal at appropriate condition in solvents. HPC has been used for a binder of medicines and can be applied for green sustainable chemistry in materials science. In this study, poly(bis-(3,4-ethylenedioxythiophene)), abbreviated as poly(bis-EDOT), film is prepared in cholesteric liquid crystals with electrochemical polymerization. We employ a dimer of EDOT (bis-EDOT) as a monomer because bis-EDOT shows good affinity with liquid crystals and the linear shape of bis-EDOT allows pre-orientation in liquid crystal prior to polymerization. The polymer film thus prepared in cholesteric liquid crystals (CLC) shows characteristic circular dichroism (CD) derived from 3-D asymmetric super structure. This study demonstrates that polymerization of the linear-shaped bis-EDOT can effectively imprint 3-D asymmetric structure from HPC as a polymer CLC matrix and form conductive polymer/non-conductive polymer composite.
Al2O3-ZrO2(95/5 wt%a) composite powders have been prepared by the coprecipitation technique . Both normal sintering and capsule-free HIP sintering have been performed under various sintering conditions. The combination of normal sintering at 1798 K and HIP sintering at 1723 K enhances the bending strength of the composites to 958 MPa . Bending strength above 1 GPa is succeeded by capsule HIPing at 1623 K. The enhancement of bending strength is discussed in connection with the sintering conditions.
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