Perpendicularly oriented columnar structure was obtained for electropolymerized polypyrrole films formed from micellar solution of anionic surfactants. The surfactants used as dopants were a class of anionic surfactant, namely, sodium salts of dodecyl sulfate (SDS) and dodecylbenzene sulfonate (SDBS). The formation process of polypyrrole films on electrode surfaces was studied with in situ atomic force microscopy,(AFM) and electrochemical quartz crystal microbalance (EQCM) methods in order to monitor the submicron structure of the grown polymers. In EQCM measurement, the frequency shift (Δf) and the resonance resistance (ΔR) of the quartz crystal electrode were obtained simultaneously. An abrupt increase in ΔR was observed for both PPy/DS− and PPy/DBS− films at about 60–100 normalmC cm−2 . Such a drastic change in ΔR, which may be associated with the emergence of the viscoelastic properties of the films, could be explained by the formation of columnar structure. In situ AFM observation clearly indicated that such a structure started to form around these critical charges. The cyclic voltammograms for the PPy/DS− and PPy/DBS− films showed sharp redox couples observed around −0.5 to 0.6 V. The redox corresponds to a cation doping/undoping process. The diffusion rate of cations for the resulting films was studied with ac impedance measurement as a function of the concentration of surfactant dopants. As the PPy film was prepared in higher concentration of the surfactant dopant, where the micelles are formed in solution, the resulting film showed a considerably higher (ca. three orders of magnitude) diffusion coefficient compared to ordinary PPy films so far reported. Such an enhanced diffusivity of ions could be attributed to a special formation process of polypyrrole in micelle solution: the mechanism is discussed here.

The anion doping‐undoping process of NBR (nitrile butadiene rubber)‐guided‐grown‐polypyrrole (PPy/NBR) film electrode was investigated by varying the precoated NBR film thickness and the acrylonitrile content in the NBR host polymer. The electrode kinetics and the morphology orientation of the PPy/NBR film were found to depend greatly on the nature of the precoated NBR film. Compared to a normally polymerized PPy film, a PPy/NBR film formed particularly with ClO4− anion showed an enhanced switching reversibility and an acceleration of the dopant movement within the polymer layer. Impedance analysis revealed that the PPy/NBR films show a clear change in their overall electrode process, from a charge transfer limiting process to a diffusion limiting process according to an increase in the precoated NBR thickness and also to a decrease in the acrylonitrile content of the NBR film. The perpendicularly formed morphology is easily formed when using NBR with less acrylonitrile. The rechargeable lithium battery with a PPy/NBR cathode shows a better charging‐discharging performance than a PPy/NBR cathode formed with a lower AN content NBR.

We analytically examine breakup phenomena of a compound liquid jet which consists of a gas or liquid core phase and a surrounding annular phase. Applying the long wave approximations to the basic equations and the boundary conditions for inviscid and incompressible fluids, simplified nonlinear equations are derived for large deformation of the jet. It is numerically shown for a doubly infinite jet that the core phase is periodically capsuled by the annular phase, whose profiles are largely affected by density ratios and velocity difference between the core and annular phases. On the other hand, for a semi-infinite jet emanating from a nozzle exit, breakup of the jet brings about encapsulation in the downstream, whose profile becomes more sensitive to input disturbances when the Weber number is small. For larger Weber number, however, the breakup profiles are almost the same as those in the doubly infinite jet. In order to see the validity of the present model, breakup profiles are also shown for the parameters used in the previous experiments.