Acid dopants

Several aspects of these networks appear inconsistent with this study. The first obvious feature is the occurrence of greater amounts of AcH than AcOH, particularly at low temperatures and oxygen partial pressures. AcH AcOH ratios greatly in excess of 1 1 have been noted for C03O4 catalysts to which acidic dopants have been added. This ratio was less than 1 1 when basic oxides were used. This point is important because according to both networks described above AcH and AcOH should be produced in equal quantities initially (refs. 2,5) Table 1 shows that AcH is unstable in our reaction conditions whereas AcOH is stable and Table 1 also shows that AcH and DA convert into AcOH in our... 

Preparation Di(Butoxyethoxyethyl) Ester of Sulphosuccinic Acid Dopant... 

To enhance the response of the polypyrrole sensor towards DMMP, acid dopants were added to the polypyrrole structure. The rational for doping polypyrrole was to introduce secondary doping sites for DMMP in the structure. Secondary doping... 

Direct polymerization of aniline in a water-toluene stirred mixture containing pTS acid dopant... 

FIGURE 7.2 Structures of sulfonic acid dopants used. 

The emeraldine salt forms of copolymers appear to be more antimicrobially effective than the emeraldine base forms of the same copolymer. It seems that the presence of an acidic functional group (-COOH) in the polymer chain improves the antibacterial efficacy of the copolymer. This could, in theory, be due to the acidic dopants on the molecular chains of the copolymers reacting with the bacteria (or other relevant microbial organism) which result in microbial death. Alternatively, it could be due to the electrostatic adherence between copolymer molecules and the bacteria, which carry charges of different polarity, the bacteria walls may break and the bacterial contents become exposed or leak out, which cause the bacteria to die [17]. 

Acrylic acid doped polyaniline exhibits sensor response in terms of the dc electric resistance on exposure to ammonia. The change in resistance is found to decrease linearly with NH3 concentration up to 58 ppm and saturate thereafter [33]. The decrease in resistance is explained on the basis of removal of a proton from the acrylic acid dopant by the ammonia molecules, thereby rendering free conduction sites in the polymer matrix. 

Almost simultaneously, another breakthrough occurred when it was realized that the protonic acid dopant could be selected or modified to act as a surfactant. Homologs of toluene sulfonic acid were the first examples examined [49], and camphor sulphonic acid proved to be one of the most interesting and promising acid surfactants [50], solubilizing polyaniline in m-creosol. 

CH3SO3H/ acetic acid dopant film cast 60 (5)... 

Polymerization on colloidal cerium oxide particles In the presence of ammonium persulfate (oxidant) and dodecylbenzene sulfonic acid (dopant)... 

In order to characterize the reaction system, the partitioning of species between solid silica and fluid phases was measured and modeled as a function of operating conditions. Also studied was the use of protic and Lewis acid dopants to further enhance reaction rates. 

R. K. Paul, C. K. Pillai, Melt/Solution Processable Conducting Polyanihne with Novel Sulfonic Acid Dopants and Its Thermoplastic Blends. Synth. Met. 2000,114, 27-35. 

Lu et al. [95] have also prepared ER fluid based on PANI-MMT nanocomposite with small particles diameter about 100-200 nm by an emulsion intercalation method. No additional surfactant is used and the aniline monomer remains excess amount in their intercalation reaction, and thus, the positive charged aniline monomer can well replace the absorbed sodium ions in interlayer of MMT. In order to further reduce the conductivity of the PANI-MMT particles prepared by the chemical oxidation of aniline in the presence of acidic dopant, the PANI-MMT particles must be immersed in NH aqueous solution. This immersed time for controlling conductivity of this nanocomposite is longer (several hours) compared with immersed time (only several minutes) of pure PANI. This may be related to the protection function of MMT layer to PANI macromolecular. The yield stress of PANI-MMT ER fluid is 7.19 kPa at 3 kV/mm, which is much higher than that of pure MMT as well as that of the mixture of PANI with clay (PANI+MMT). 

The emeraldine salt of polyaniline which is one of the three different forms of polyaniline—leucoemeraldine (the fully reduced state], emeraldine (the half oxidized state] and pernigraniline (the fully oxidized state] (Fig. 8.1]—is electrically conductive while the others are insulators. Conventional chemical synthesis of polyaniline is based on an oxidative polymerization of aniline by using an oxidant in the presence of a strong acid dopant in the reaction mediunL ... 

Chemical Polymerization with Sulfonic Acid Dopants... 

Innovative microstructures have been produced by self-assembly during electropolymerization in the presence of surfactants. Dai and coworkers have recently shown that bowl-shaped microcontainers of polypyrrole can be produced by stabilizing H2 gas bubbles on the electrode surface [79]. Carboxylic acid dopants have also been used, resulting in hollow nanotubes of polyaniline [80]. 

In the vast majority of cases, phosphoric add has been used as acid dopant for PBI or other basic polymers. Early research, however, also considered doping with other adds, including sulfuric and perchloric acids (Xing and Savadogo, 1999). More recently, and with the particular objective of avoiding leaching of the addic component from the membrane in the presence of a liquid feed or, polymerised organic derivatives of phosphoric add have... 

FIGURE 21.9 Mass spectra of RDX. (A) Without any dopant gas, (B) with dichloromethane dopant, and (C) with lactic acid dopant. 

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