Anodic polymerisation of aniline and methylsubstituted derivatives: ortho and para coupling

4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces

“…This route involves electropolymerisation of 4-azidoaniline at the GC surface, which resulted in the visible formation of red polymer strands at the GC disk, and then coupling of the surface-immobilised azido groups to ethynylferrocene via the CuAAC click reaction. To the best of our knowledge, there is no report on the electropolymerisation of 4-azidoaniline in the literature, even if examples of electropolymerisation of 4-substituted aniline compounds, such as para-nitro-aniline or 4-methylaniline for example, are documented [19,20]. Fig.…”

“…4 shows high resolution XPS spectra of N(1s) region. Before click reaction, two peaks at 401 eV and 404 eV are observed for route C, while three peaks at 399.6, 401 and 404 eV are present for route R. The peak at 404 eV is attributed to the presence of azide groups, as reported in the literature, confirming immobilisation of N 3 groups at GC surface in both cases [3,[33][34][35] The intensities of the N(1s) peaks are weaker for route C than for route R, indicating that less azide groups are present at the surface modified by route C compared to route R. The low amount of azide groups immobilised at the electrode using route C prior to the click reaction can be explained by the fact that the electropolymerized films stop growing after few cycles under the electropolymerisation conditions used; indeed the redox signal corresponding to the formation of the electrodeposited polymer stops growing after three voltammetric cycles certainly due to the fact that the para-position of the aniline is occupied by N 3 groups, thus limiting the electropolymerisation process to branching at the ortho-position [20,23]. The azide group could also be involved in the polymer growth at the para-position, and so limit the free azides to the ends of the polymer strands, or some of the azide groups may have been eliminated during paradirection polymerisation [21].…”

“…The direct electropolymerisation of the newly synthesised 3 (route A) was first investigated through the possibility of electropolymerisation of its aniline group [18][19][20][21][22]. As electropolymerisation through branching at the ortho-position of the aniline would result in a greater number of attached ferrocene versus the commonly favored growth in the para-direction (and possible elimination of the para-group [21]), a potential step method was used rather than potential sweep, as the former is believed to increase the rate of ortho-coupling [23].…”

Aniline oligomers versus polyaniline

“…The first group assumes that aniline molecules are linked entirely in para ‐positions,67–73 as they appear in PANI. The second group admits also the possibility of the ortho ‐coupling of aniline units at the oligomeric stage,74 leading to phenazine‐like constitutional units 1–8, 27, 30–32, 34, 35, 54. The combination of these approaches is represented by the direct dimerization of p ‐semidine to phenazine‐like units 4, 18, 65, 75.…”

Microporous Membranes Based on Polyaniline via Thermally Induced Phase Separation

“…It should be noted that in the above-mentioned electrochemical applications, PANI membranes with thickness on the order of 1µm were electro-deposited on the surface of noble metal foils. It has been indicated by many studies [5,6] that PANI membranes with a thickness larger than 10 µm could hardly be obtained via electro-or chemical-deposition method.…”