Solvent-induced microstructure changes and consequences for electrochemical activity of redox-active conducting polymers

The solvent-induced collapse of a redox-active conducting polymer and the consequence on its DNA-sensing ability

“…As we have previously discussed for different polymers, the impedance of the films can be represented with a dual transmission line model, that becomes practically indistinguishable from a simple series-parallel representation as the film impedance increases with collapse of the microstructure [23]. This simplified electrochemical model is presented in Fig.…”

“…The electrochemical stability of CPs is especially important for those CPs that are synthesized in an organic solvent (due to good film-forming properties in the organic solvent) and then used in aqueous buffer solutions as biosensors because of the possibility of microstructural changes occurring in the CP as it reaches a new equilibrium state [21,22] in the aqueous solution. Our previous study examined the microstructural changes of PEDOT film and a terthiophene film functionalized with acrylic acid (PTAA) [23]. The PEDOT film maintained its microstructure and electroactivity longer than PTAA film in aqueous solution.…”

“…In this work, in an attempt to prevent such microstructure collapse, another terthiophene monomer was synthesized, 5-(2 0 :2 00 , 5 00 :2 000 -terthiophene)-3 00 -yl)] (2E, 4E)penta-2,4-dienoic acid (TPDA) (see Scheme 1), which was subsequently electropolymerised into the polymer poly(TPDA) (PTPDA), grafted with oligonucleotides (ODNs) and its ability to withstand microstructural collapse in aqueous solution and its DNA-sensing ability was evaluated using EIS according to the similar methodology as in [23]. The longer side chain in TPDA possessed an additional double bond (compared to TAA) and was hoped to endow the polymer with greater electrochemical stability arising from the additional delocalized p orbitals [24].…”

Functionalized polythiophenes: Recognition materials for chemosensors and biosensors of superior sensitivity, selectivity, and detectability

“…This monomer was potentiodynamically electropolymerized to form films on the surface of a glassy carbon electrode (GCE) and an Au electrode of a QCR for electrochemical impedance spectroscopy (EIS) and PM transduction, respectively (Table 2). Neutravidin was irreversibly Microstructural changes of films of terthiophene functionalized with acrylic acid (PTAA) [141] or with pentadienoic acid [142] have been examined (Scheme 15). The microstructure of both films was sustained in organic solvents, but collapsed in aqueous buffer solutions.…”

“…[3',3'''-bis(hydroxymethyl)-2':2'',5'':2'''-(terthiophene)-3''-yl]acrylic acid (HTAA), was synthesized (Scheme 15)[144] to mitigate the PT microstructure collapse in aqueous solutions[141,142]. Indeed, this collapse was significantly diminished compared to that of the previously prepared terthiophene polymers.…”