Conducting polymer scanning electron

In 1994, we reported the dispersion polymerization of MM A in supercritical C02 [103]. This work represents the first successful dispersion polymerization of a lipophilic monomer in a supercritical fluid continuous phase. In these experiments, we took advantage of the amphiphilic nature of the homopolymer PFOA to effect the polymerization of MMA to high conversions (>90%) and high degrees of polymerization (> 3000) in supercritical C02. These polymerizations were conducted in C02 at 65 °C and 207 bar, and AIBN or a fluorinated derivative of AIBN were employed as the initiators. The results from the AIBN initiated polymerizations are shown in Table 3. The spherical polymer particles which resulted from these dispersion polymerizations were isolated by simply venting the C02 from the reaction mixture. Scanning electron microscopy showed that the product consisted of spheres in the pm size range with a narrow particle size distribution (see Fig. 7). In contrast, reactions which were performed in the absence of PFOA resulted in relatively low conversion and molar masses. Moreover, the polymer which resulted from these precipitation... 

Cyclic voltammetry was performed with the ADH-NAD-MB/polypyrrole electrode in 0.1 M phosphate buffer (pH 8.5) at a scan rate of 5 mV s l. The corresponding substrate of ADH caused the anodic current at +0.35 V vs. Ag/AgCl to increase. These results suggest a possible electron transfer from membrane-bound ADH to the electrode through membrane-bound NAD and MB with the help of the conductive polymer of polypyrrole. 

Methods of Characterization The polymers were characterized by four-probe electrical conductivity measurements between room temperature and liquid nitrogen, electron spin resonance (Varlan E-line series), scanning electron microscopy (Hitachi 520), cyclic voltammetry (Princeton Applied Research Instruments), and uv-vlsl-ble spectroscopy (Perkin Elmer 330). 

Another approach to deposit conducting polymers can be achieved by photochemical polymerization of the monomer precursors. This procedure provides a means by which different composites (metals and/or various alloy materials with or without biomolecules) can be deposited from an electrolyte onto a non-conducting surface. Such a procedure was optimized and applied for polymerization of pyrrole in the presence of metal nanoparticles [61]. Photopolymerized films containing metals analyzed by environmental scanning electron microscopy (SEM) appeared to be typical of amorphous polypyrrole in which bright Ag particles were found on the surface (Fig. 7.6). 

Fig. 4.10 Photograph and scanning electron micrograph of three-dimensionaUy ordered macro-porous polyimide and composite membrane consisting of macroporous polyimide and proton conductive polymer...

Other workers have used additives to enable the preparation of effectively water-soluble conductive polymer colloids. As early as 1986, Bjorklund and Liedberg102 observed that when pyrrole was oxidized by FeCl3 in the presence of aqueous methylcellulose (MWt 100,000), a PPy/methylcellulose sol was formed that could be characterized by scanning electron microscopy. Thin films could be obtained from the sol, exhibiting a conductivity of ca. 0.2 S cm-1. Subsequently, a range of neutral, water-soluble steric stabilizers such as poly(vinylalcohol), poly(ethyleneoxide) (PEO), or poly(vinylpyridine) have been successfully... 

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