Diarylethenes for Memories and Switches

Recent developments in the chemistry of halogen-free flame retardant polymers

The gas sensors fabricated by using conducting polymers such as polyaniline (PAni), polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.

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Gas Sensors Based on Conducting Polymers

In this paper, the recent developments and the characteristics of membrane separators for lithium-ion batteries are reviewed. In recent years, there have been intensive efforts to develop advanced battery separators for rechargeable lithium-ion batteries for different applications such as portable electronics, electric vehicles, and energy storage for power grids. The separator is a critical component of lithium-ion batteries since it provides a physical barrier between the positive and negative electrodes in order to prevent electrical short circuits. The separator also serves as the electrolyte reservoir for the transport of ions during the charging and discharging cycles of a battery. The performance of lithium-ion batteries is greatly affected by the materials and structure of the separators. This paper introduces the requirements of battery separators and the structure and properties of five important types of membrane separators which are microporous membranes, modified microporous membranes, non-woven mats, composite membranes and electrolyte membranes. Each separator type has inherent advantages and disadvantages which influence the performance of lithium-ion batteries. The structures, characteristics, manufacturing, modification, and performance of separators are described in this review paper. The outlook and future directions in this research field are also given.

A review of recent developments in membrane separators for rechargeable lithium-ion batteries

The synthesis, properties and applications of polypyrrole (PPy), a representative of conducting polymers, are reviewed. Chemical and electrochemical methods for the preparation of PPy and PPy films and the effect of the reaction conditions on the properties of the polymer produced are discussed. The mechanisms of electrochemical polymerisation of pyrrole are compared. The physicomechanical properties of the polymer, its morphology and structure are discussed. The mechanism of charge transfer in PPy is considered within the framework of the model of quasi-equilibrium concentrations of polarons and bipolarons. The methods for modification of the electrochemical performance of PPy are reviewed, in particular, synthesis of PPy from pyrrole derivatives with the appropriate electroactive groups and introduction in the PPy of electroactive dopant anions and the effect of those on the electrochemical performance of PPy films are considered. Examples of the use of PPy are given and the prospects for its application in various areas are discussed. The bibliography includes 254 references.

https://iopscience.iop.org/article/10.1070/RC1997v066n05ABEH000261/pdf

Polypyrrole : a conducting polymer; its synthesis, properties and applications

Aromatic alternating copolyimides have been synthesized by the reaction of various precursors for imido diamine with 6FDA. The alternating copolyimides appeared to have enhanced solubility in organic solvents such as DMAc, NMP, and DMSO when compared with the corresponding random isomers. Various NMR experiments including 2-D COSY spectra have been performed for the characterization of the alternating copolyimides. On the basis of the NMR results, the synthetic pathway of the aromatic copolyimide through the reaction of a precursor for imido diamine with a dianhydride leads to a copolymer with a complete alternating sequence without randomization during the cyclization reaction

Synthesis and Characterization of Soluble Alternating Aromatic Copolyimides

Electrochemical properties of polyaniline doped with poly(styrenesulfonic acid)

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene was prepared and used in initiating polymerization of 2-methyl-2-oxazoline to produce six-armed, star-branched polymers. Monofunctional initiator, N 3 P 3 (OC 6 H 5 ) 5 (OC 6 H 4 -p-CH 2 Br), was also prepared and used for initiating the polymerization of 2-methyl-2-oxazoline to result in linear polymers. The linear polymer (DP= 31) with a bulky hydrophobic head and a hydrophilic chain exhibited nonionic surfactant behavior, forming micelles above a polymer concentration of about 0.1 wt %

Preparation of Star-Branched Polymers with Cyclotriphosphazene Cores

Poly(4-anilino-1-butanesulfonic acid) sodium salt was synthesized from the electrochemical oxidation of 4-anilino-1-butanesulfonic acid sodium salt, which was readily obtained from aniline and 1,4-butane sultone. The resulting water-soluble polymer has shown much higher redox cyclability than unsubstituted polyaniline, which was demonstrated by an in situ spectroelectrochemical and a cyclic voltammetric study

Redox Cyclability of a Self‐Doped Polyaniline

Electrochromic properties of poly(aniline N-butylsulfonate)s (PANBUS) coatings on indium-tin oxide (ITO) glasses exposed to an ion conducting polymer films were investigated. The ion conducting polymer films were prepared via photocross-linking reactions of methoxy polyethylene glycol-mono methacrylate with tri(propylene glycol) diacrylate in the presence of a photoinitiator and LiClO{sub 4}. Mechanical properties of the electrolyte film were enhanced by introducing styrene or butylmethacrylate into the polymer network. Color contrast and optical response of the PANBUS-based window were improved by adding Nafion into the electrolyte. The electrochromic (EC) window assembled with PANBUS, Nafion containing polymer electrolyte film, and tungsten trioxide coated ITO glass (type 2) required less energy for operation ({+-}1.5 V) compared to the EC window without tungsten trioxide film (type 1, {+-}2.0 V). By applying {+-}1.5 V, optical density of the type 2 window changed from zero to maximum of 1.2, corresponding transmission change of higher than 95%. Lifetime tests show that the type 2 window could support more than 2.3 {times} 10{sup 3} cycles, of 60 s duration.

Suh Bong Rhee

Papers

Synthesis and Characterization of Soluble Alternating Aromatic Copolyimides

Electrochemical properties of polyaniline doped with poly(styrenesulfonic acid)

Preparation of Star-Branched Polymers with Cyclotriphosphazene Cores

Redox Cyclability of a Self‐Doped Polyaniline

Electrochromic Window Based on Poly(aniline‐N‐butylsulfonate)s with a Radiation‐Cured Solid Polymer Electrolyte Film