To date, polyaniline (PANI) has been synthesized in pure water. Aside from this, the application of PANI as a conducting polymer could be extended if it can be effectively synthesized in seawater, which constitutes 70% of the surface of the Earth. The production of functional plastics using natural resources without any additional purification would improve industrial production and enhance the comfort associated with our daily life. However, no examples of the effective application of seawater to PANI synthesis have been reported. Herein, PANI with an electrical conductivity of ~10−2 S/cm was synthesized in seawater as the reaction solvent. The electron spin resonance measurements confirmed the role of the polarons of PANI as charge carriers. In addition, a PANI/silk composite was prepared in seawater to produce a conducting cloth for further applications. The performance of the PANI prepared in seawater as the solvent was comparable to that of the PANI prepared in pure water. Thus, the proposed method allowed for the production of the conducting polymer via a convenient and low-cost method. This is the first study to report the usage of seawater as an abundant natural resource for synthesizing conducting polymers, promoting their wide application.

Polyaniline (PANI) was prepared in the presence of the acidic dye scarlet 3R. Color tuning was performed on PANI through doping–dedoping processes and by changing the solvent used during the optical absorption spectroscopic measurements. The chemical structure of the resulting polymer–dye composite was analyzed using infrared absorption spectroscopy, and it showed the occurrence of secondary doping in m-cresol. The shape of the UV–Vis optical absorption spectra for the composite solution is dependent on the types of organic solvents used during the analysis, which was influenced by the conformation of PANI and the ionic interactions between PANI and scarlet 3R.

We describe a four‐step process [solvent vapor treatment, liquid crystal formation, magnetic orientation, and crystallization (VLMC)] for producing oriented helical polyisocyanides with crystal‐like structure. We synthesized a series of ortho‐alkyl groups substituted with poly(phenyl isocyanide), and characterized the polymer structure using polarizing optical microscopy, scanning electron microscopy, and X‐ray diffraction. The results demonstrated that the polymer has a crystal‐like structure and the sample forms cholesteric liquid crystal phase. Vapor treatment of polymer films under a magnetic field produced an aligned fiber structure at the submicron level and demonstrated magnetic alignment and formation of a solvent vapor‐induced polymer crystal. These results demonstrated formation of a polymer with a one‐handed helical structure, formation of a liquid crystal and polymer crystal via solvent vapor treatment, and magnetic alignment of a textile‐like polymer crystal domain.

Poly(bis‐3,4‐ethylenedioxythiophene) was synthesized by electrochemical polymerization in cholesteric liquid crystal (Ch*LC) in the presence of 7,7,8,8‐tetracyanoquinodimethane (TCNQ). TCNQ acted as a supporting salt and a molecular dopant against the resultant poly(bisEDOT) to form a donor–acceptor‐type polymer charge‐transfer (CT) complex. Because a three‐dimensional (3D) one‐handed chiral structure was imprinted from the matrix chiral liquid crystal, the resulting polymer with TCNQ molecular doping displayed optical activity in the circular dichroism absorptions. This result indicates the production of optically active CT species comprising the polymer and the low‐molecular‐weight acceptor. The intermolecular chiral CT complex formed a one‐handed helical structure. This method is referred to as “CT complex liquid crystal (LC) electrochemical polymerization” to produce the helical polymer CT complex as atropisomers. Further, the optically active CT of the polymer is referred to as “CT chiralions.” The CT formation resulted from the molecular doping of TCNQ in the chiral polymer prepared in the helical LC matrix. As a result, molecular doping and molecular‐imprinting polymerization in the LC produced CT chiralions. The two‐step electrochemical polymerization in one‐pot polymerization developed in this study allowed the results to form a double‐layer fingerprint with a moiré‐like pattern.

Synthesis of polyaniline in the presence of fullerene nanotubes (nanocarbons) in water was carried out with oxidative polymerization. The surface of the sample showed metallic emerald green color in bulk like the brilliance of encrusted gemstones. The composite showed unique magnetic behavior, such as microwave power-dependent magnetic resonance as magnetic spin behavior and macroscopic paramagnetism with a maximum χ value at room temperature evaluated with superconductor interference device. Surface structure of the composite was observed with optical microscopy, circular polarized differential interference contrast optical microscopy, scanning electron microscopy, and electron probe micro analyzer. Polymer blends consisting of polyaniline, nano-carbons, and hydroxypropylcellulose or acryl resin with both conducting polymer and carbon characters were prepared, which can be applied for electrical conducting plastics. The combination of conducting polymer and nano-carbon materials can produce new electro-magneto-active soft materials by forming a composite. This paper reports evaluation of magnetic properties as a new point of nanocarbon and conducting polymer composite.