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In this research a comparative study of the starting unit chain length effect on the electropolymerization of thiophene or its oligomers was carried out considering mono (1Th), bi (2Th), ter (3Th), tetra (4Th) and sexi (6Th)-thiophene as starting units.The deconvolved transient allows stating that the growth of polythiophene (PTh) employing each of the starting units have the same predominant contribution to the nucleation and growth mechanism (NGM). The others contributions disappear as the length of the starting unit chain increase. The results were validated by scanning electron microscopy (SEM) of PTh deposits obtained onto SnO 2 coated glass, following a potential pulse program.Besides of corroborating the electropolymerization model, this study suggested the possibility of designing and performing suitable experiments leading to the attainment of electro-deposited conductive polymers bearing a desired morphology, appropriated for prospective applications.

Cellular immunity to herpes simplex virus type 1 (HSV-1) in 12 volunteers with recurrent herpes labialis was evaluated by means of two microassays. In the blastogenesis assay, lymphocytes were incubated with tissue culture cells persistently infected with HSV-1. Uninfected cells were used as controls, and a blastogenic index was calculated. The mean blastogenic index (plus or minus SD) for subjects with recurrent herpes labialis was 26.9 (plus or minus 8.3); the mean blastogenic index (plus or minus SD) in control donors with antibody to HSV-1 was 13.4 (plus or minus 7.2). The difference between these values was statistically significant (t equals 4.154; P smaller than 0.001). In the cytotoxicity assay, cells of the same persistently infected line were used as target cells, and release of 51-Cr from these cells or from control cells served as the index of lymphocyte reactivity. Specific immune release attributable to HSV-1 averages 3.7% (plus or minus 1.8%) in subjects with recurrent herpes labialis, compared with 23.1% (plus or minus 9.8%) in controls (t equals 6.135; P smaller than 0.001). These data suggest a dissociation between mechanisms of cellular immunity, with enhanced lymphocyte blastogenesis but decreased cytotoxicity. Recurrent herpes labialis may thus result from subtle cellular immune deficiency involving at least one of the efferent mechanisms.

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Polyterthiophene (PTT) thin films have been electrosynthesized using potentiodynamic and potentiostatic methods. The optimal experimental conditions to prepare organic solar cells were determined by deposition of films on platinum and then the process was adapted to an indium tin oxide substrate. Surface morphology of films deposited by potentiostatic methods proved to be more homogeneous than films obtained by potentiodynamic methods. When PTT is employed in photovoltaic cells, the best results are attained using the latter technique. In these solar cells, the polymer is used as electron donor while N,N'- diheptyl-3,4,9,10-perylene-bis-carboximide (PTCDI-C7), deposited by vacuum sublimation, was the electron acceptor. The short circuit current is systematically small, probably due to the roughness of the polymer which induces high series resistance. In any case, it was demonstrated that the electrochemical method is suitable to prepare polymeric layers of electronic devices.

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In the present work the obtention of poly-o-aminophenol (POAP) at high potentials on conducting glass (SnO 2 : F) is reported. The synthesis was carried out by continuous potential cycling in a 1×10 -3 M o-aminophenol (OAP), 0.1 M hydrochloric acid, and 0.1 M potassium chloride solution between -0.2 and 1.5 V at 0.05 V·s -1 vs Ag│AgCl. The polymer growth was followed by cyclic voltammetry, UV-vis spectra, and AFM characterization. The SnO 2 : F modified electrode (SnO 2 : F/POAP) was tested in the electro-oxidation of ascorbic acid (AA) in phosphate buffer solution. This coating showed an important electrocatalytic effect because a negative anodic shift of 0.4 V with respect to a bare SnO 2 : F glass electrode was observed.