Conducting polymers ammonium persulfate

Hanks has investigated the chemical polymerization of complexes 253-256.143144 With appropriate oxidizing agents (e.g., phosphomolybdic acid or /-butyl ammonium persulfate), film-forming conductive (10 2 to 10 3Scm 1) polypyrroles were generated. The polymer from Pd11 complex 255 was luminescent, while the other polymers were nonemissive. Dodecylbenzenesulfonate counterions improved the film quality of cast polymers. 

Polyaniline results from the reaction of aniline with ammonium persulfate in aqueous HCI. The reaction produces polyaniBne as a dark blue powder with a conductivity of 5 (ohm-cm) The structure of the conducting form of the polymer is believed to be the di-iminium salt ... 

The in situ polymerization of aniline to form an electrically conductive textile was also first reported by Kuhn and coworkers [78,79] in which the polyaniline was deposited onto a textile substrate from an aqueous solution containing aniline, ammonium persulfate, hydrochloric acid, and either the disodium salt of 2,6-naphthalenedisulfonic acid or 1,3-benzenedisulfonic acid. In these studies, the polymerization conditions were controlled in order to deposit the polyaniline layer only onto the textile support with no polymer precipitating in the bulk liquid phase. This was accomplished by using dilute solutions of aniline (0.03 M). A subsequent study by Tzou and Gregory [92] on the deposition of polyaniline to nylon-6 fibers was focused on investigating the reaction kinetics of the chemically oxidative polymerization of aniline... 

As mentioned earlier in situ approach has also been used for the synthesis of conducting polymer-metal hybrid nanocomposites. Xu et al. [35] have reported the decoration of PPy nanotubes with gold nanoparticles by an in situ reduction process. They prepared PPy nanotubes by MO-FeCl3 self-degrade template method and then reduced HAuCLi within PPy nanotubes in the presence of different surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and Tween-80. Nanowires of silver PAni nanocomposites have been reported via in situ polymerization method [36]. In this method aniline is oxidized by ammonium persulfate (APS) in the presence of dodecylbenzene sulfonic acid (DBSA) and silver nitrate (AgN03). In another approach gold-PAni core-shell... 

A mixture consisting of water (190 g), ethyl alcohol (10 g), hexadecyl acrylate (70 g), hexyl acrylate (25 g), methyacrylic acid (5g), 3.2% sodium dodecyl sulfate, and ammonium dodecyl benzene sulfonate (5 g) was charged into a reactor and degassed for 30 minutes. Potassium persulfate (0.4 g) was then added, and the polymerization was conducted for 4 hours at 70°C under nitrogen. After the polymer was isolated, a sharp DSC endotherm was observed at 22.5°C. 

The polymerization process is performed by using one of the following three methods emulsion polymerization, suspension polymerization or bulk polymerization. The first and oldest method is rarely used (around 10% of PVC is produced this way). The production can be periodic or continuous. In the continuous method, there is a negative effect of the polymer being deposited in autoclaves, which can lead to deterioration in heat exchange and an increase in the amoimt of coagulum (non-coUoidal particles of latex). Emulsion polymerization is conducted in the presence of initiators dissolved in water, i.e., non-organic oxides (ammonium, potasium persulfate), emulsifiers (mostly anionic alkylbenzyl sulfonate, fatty acids salts, alkylphenyl ethoxides and fatty acids). The selection and the amount of the emulsifier is crucial since it affects the properties of latex, the particle size, the stability, and the tendency of the powder to cake. Other aids used in the process of polymerization are buffers phosphates and sodium carbonate. 

---