Continuous EDOT •+ generation by IET and ensuing radical coupling steps ultimately lead to the formation of cationic PEDOT oligomers that also coordinate with TB -to maintain electroneutrality (Fig. ). These coupling steps result in the release of protons on the organic side of the ITIES (Supplementary Fig. ) that will be stabilised by the PEDOT thin film itself or by water present inside the film. 24 Interfacial adsorption involving ion-pairing between the cationic PEDOT oligomers and aqueous electrolyte anions (herein SO4 2-) takes place once the oligomers reach a critical size after an induction period (Fig. (ii)). SO4 2-anions displace the weakly coordinating organic TB -anions during interfacial adsorption, ultimately becoming the sole dopant anion in the PEDOT thin film. This deposition process is driven by the energetically favourable reduction of the interfacial tension (𝛾) between the two repulsive phases upon oligomer adsorption. Setting Δ o w 𝜙 slightly negative of the potential of zero charge (PZC) is optimal for oligomer adsorption, ensuring the presence of a sufficient concentration of SO4 2-at the L|L interface to participate in ion-pairing. Thus, as the IET and oligomer interfacial adsorption steps take place at different applied Δ o w 𝜙, potentiodynamic or multi-step potentiostatic are favoured over single-step potentiostatic electrochemical techniques. Also, a negative Δ o w 𝜙 will facilitate the pumping of protons, generated on the organic side of the ITIES during the IET/radical coupling process at a positive Δ o w 𝜙, to the aqueous phase via either direct ion transfer or the Grotthuss mechanism through the PEDOT thin film (Supplementary Fig. ).