Analysis of Conjugated Polymers Conductivity by in situ Electrochemical‐Conductance Method

Abstract

The in situ electrochemical‐conductance method is presented as an important electrochemical characterization tool for gaining insight into the chemical and electrical behavior of π‐conjugated polymers and electroactive materials. Important information about conductivity models, the type of charge carrier, and the carrier‐transport pathways as well as explanations of different phenomena related to charge and mass transport can be extracted from the obtained analyses. Using conveniently modified polymers, this method enables the development of a wide range of conductometric sensory devices. This Minireview summarizes the historical development of the in situ electrochemical‐conductance method, describes the systems used, explains details of the calculations, and discusses recent advances and applications.

Nickel(II) Complex of N4 Schiff Base Ligand as a Building Block for a Conducting Metallopolymer with Multiple Redox States

“…In situ conductance measurements were performed on poly-[NiAmben] in order to gain more insight into its electrochemical behavior and related charge transfer phenomena. Reliable values of conductivity cannot be calculated from the experimental data because of inhomogeneity of the polymer film and challenges in the determination of its thickness but the conductivity behavior of the polymer can be indirectly evaluated using its conductance G [ 33 ]. In this set of experiments, the trends in conductance have been followed as a function of potential.…”

“…The bell-shaped conductivity indicates that poly-[NiAmben] rather behaves like a redox polymer [ 36 ] or a conjugated polymer with a limited number of accessible mixed-valence states [ 37 , 38 , 39 , 40 ]. According to the mixed-valence model, the maximum in the bell-shaped conductance profile is reached when half the sites of the redox state are charged [ 33 , 41 ]. Two partially overlapping conductivity regimes are found in poly-[NiAmben] upon charging in the range of potentials from −0.34 V to 0.65 V, which indicates that two mixed valence systems are generated in the polymer film [ 39 , 40 ].…”

Sodium‐Ion Selectivity Study of a Crown‐Ether‐Functionalized PEDOT Analog

“…In order to provide more information about this new polymer, insitu electrochemical conductance experiments were carried out. [35] A characteristic sigmoidal signal for the conductance (G) as a function of the potential was obtained (Figure 2), with a maximum value of ~ 75 mS. A negligible loss of conductance (0.1 %) in this potential interval was obtained, thus, the decrease of charge can be attributed exclusively to the loss of soluble electroactive material. The full charge/discharge process presented a hysteresis value of 150 mV (ΔEG) for the conductance signal (evaluated at the half-wave G vs E plot).…”

A Novel Cobalt Metallopolymer with Redox-Matched Conjugated Organic Backbone via Electropolymerization of a Readily Available N4 Cobalt Complex

“…A constant bias of 5 mV was applied between the combs of the interdigitated electrode and the flowing current was measured as a function of potential. The conductance of the polymer was calculated from the measured current between the combs by applying Ohm's law [31]. The polymer deposition process was terminated when the conductance reached a plateau (8 cycles), which indicated that the polymer completely filled the gap.…”

“…The EQCM method allows to trace ion and solvent dynamics driven by redox switching in the polymer film during electrochemical charging and discharging [30]. Changes of conductivity with electrochemical doping of the polymer probed by the in situ electrochemical conductance method [31] allows to independently recognize the presence and mobility of different charged states. We use the combined results obtained by in situ electrochemical and spectroelectrochemical techniques to gain insight into the extent of redox matching of the organic backbone and metal centers in poly-[Co(Amben)] films.…”