PROPERTIES OF POLY(PYRROLE) FILMS ELECTROCHEMICALLY SYNTHESIZED IN THE PRESENCE OF SURFACTANTS

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New functionalized oligothiophenes. Properties and applications to photodetection

A series of oligothiophenes nT(up to 6T) substitued at the ends of the chain by electronic donors(D) or acceptors(A) has been prepared. The electrochemical study of the soluble species allowed us to quantify the effect of substituents. The optical properties of the compounds have shown the existence of charge transfers at the excited state. The semiconducting properties of thin films have been investigated in the aim of applications in electronic devices. The photosensiblity in symmetrical and unsymmetrical contacts has been studied in visible area. The low junction yield (18%) suggests substantial trapping and recombination rate

POLYPYRROLE DODECYL-SULFATE - EFFECTS OF DIFFERENT SYNTHESIS CONDITIONS

We have studied in detail the effects of synthesis conditions, such as current density and sodium dodecylsulfate electrolyte concentration, on the electrical and mechanical properties of polypyrrole. Flexible and self-supported films were electrochemically obtained using an aqueous solution containing pyrrole and sodium dodecylsulfate. The conductivity (2-20 S/cm) of the films increases with increases in either the current density or the electrolyte concentration. This behavior is caused by the structural changes induced by the different kinetics of film formation. Results indicate that the dodecylsulfate anion, incorporated as dopant in the polymer, renders it flexible with tensile strength in the order of MPa.29222523

ELECTROCHEMICAL STUDY OF POLYPYRROLE DODECYL-SULFATE

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Démonstration électrochimique de l’existence des π-dimères de radicaux-cations d’oligomères de thiophène en solution

Plusieurs oligothiophènes substitues en position α,α' de differentes longueurs ont été étudiés par voltamétrie cyclique dans l'acétonitrile et dans un mélange 30/70 d'acétonitrile et de toluène. Le domaine d'existence du π-dimère a pu être déterminé par la variation des potentiels rédox avec la température et la concentration initiale

Cross-linking effect on thermal, conducting and electrochemical properties of an elastomeric polymer electrolyte

Complexing salts, like lithium perchlorate, form interesting polymer electrolytes with terpolymers containing branched ether derivatives, which can be cross-linked, depending on the allyl glycidyl ether group content. Using thermal and electrochemical techniques, the effect of polymer cross-linking upon the properties of the resulting electrolytes has been estimated. It is shown that increasing the salt concentration intensifies the stiffness of the terpolymer network or the linear/branched one and the glass transition temperature consequently rises. Both electrolyte systems investigated in this work present good thermal stabilities up to 270 degreesC and ionic conductivities of 10(-4) S cm(-1) at 30 degreesC with 8 wt.% of LiClO4. Cross-linking does not severely affect the electrolyte conductivity but very significantly enlarges the electroactivity window (from 3 to 5 V) and improves the mechanical stability. The thermal dependence of the conductivity revealed a particular conduction mechanism attributed to the presence of short mobile chains due to the high polydispersity of the terpolymer. Thermal, electrical and special electrochemical properties suggest the inclusion of this material into the available polymer electrolytes for developing new electrochemical applications. (C) 2003 Elsevier Science B.V. All rights reserved.1594173230131