The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

Abstract

Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in one-tenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators. ABSTRACT: Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in onetenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators.

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

“…This suggests that the presence of perchlorate leads to an increase in the twisting of the monomeric units, leading to a slight chain shortening. Macroscopically, such shortening is associated with a change in volume that, as described in different papers [62,66,67] and in Figure 6, could be responsible for the polymer degradation when submitted to electrochemical cycles.…”

Selectivity and Efficiency of Conductive Molecularly Imprinted Polymer (c-MIP) Based on 5-Phenyl-Dipyrromethane and 5-Phenol-Dipyrromethane for Quorum Sensing Precursors Detection

“…Moreover, it was possible to observe a trend of current attenuation when the template concentration increased vs. the constant monomer concentration in solution. It is believed that this result could be due to the different ratio template to monomer, which is responsible for generating complexes with different stoichiometry and different diffusion coefficients [35].…”

“…However, a progressive decrease of the net increment of mass per sweep during deposition was observed. According to the literature, several reasons could explain the observed behavior, as a modification of diffusion of the electroactive species to/from the electrode surface or the intervention of steric hindrance [35][36][37][38]. Oligomeric species that are not electrically conductive are reported to be formed during polymerization and these were either embedded into the film with consequent alteration of its uniformity and conductivity and/or they were involved in side reactions of termination that shuttled the radical cations responsible for the polymerization process [39,40].…”

Patterning and electrical interfacing of individually controllable conducting polymer microactuators

“…In the previous tri-layer actuators [13,19], PPy(TFSI) was synthesised at -33 °C, since the properties of PPy are improved by synthesis in organic solvents at low temperatures [20]. However, due to the absence of a low temperature freezer PPy was synthesized at either -18 °C or room temperature.…”