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Photoinduced absorption data for polyaniline films in two forms, emeraldine base (EB) and emeraldine salt (ES), are presented and discussed. Electrochemically synthesized films were excited with laser pulses of large intensity (the energy =2 eV, the pulse duration = 8 ps, the pulse energy up to 10 mJ/cm'). Optical spectra of the EB and ES films in the temperature range from 298 to 363 K are also studied. The polymer film is presumed to be a three-dimensional (3D) system of long finite conjugated fragments of polymer chains. Considering each fragment integrally and taking into account the electronic polarization energy ( =1.5 eV) for a charge in the film, the 3D model of a charge-transfer exciton is proposed. The low-energy absorption of EB and ES and the electronc processes in photoexcited films are interpreted within the framework of the proposed model, avoiding the commonly adopted approach of an isolated polymer chain.

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Thin film titanium/poly-para-xylylene nanocomposites with controlled Ti content are prepared by vacuum coevaporation and cocondensation of Ti and paracyclophane. The structure and chemical composition of as-deposited samples and the changes of electrical resistivity, which they undergo upon heating, are studied by atomic force microscopy, optical absorption spectroscopy, and the temperature coefficient of the electrical resistivity. It is shown that vacuum coevaporation results in the production of nanocomposite thin films with average Ti particle size of 10–50 nm. The inorganic phase is shown to be amorphous Ti for the samples with high metal content, whereas for the low-filled nanocomposites it consists of amorphous titanium oxide. Two types of kinetics of the nanocomposite oxidation process have been found and modeled by (i) inverse logarithmic and (ii) logarithmic functions depending on the metal content within the thin film. After a long preconditioning period in air the electrical conductivity of the thin film nanocomposites was carefully investigated by two-probe DC measurements. A strong correlation between the concentration of Ti in the thin films and the electrical conductivity dependency on temperature is found and modeled by a heterogeneous model of conductivity.