The vapor phase polymerization (VPP) technique is used to produce thinfilms of poly(3,4-ethylenedioxythiopene) (PEDOT) in which the Fe(III)Tosylateoxidant is altered. The oxidant is changed with the addition of an amphiphilicco-polymer having different molecular weights, namely 2800 Da. and 5800 Da.Resulting PEDOT films produce conductivities of ≈1500 and ≈3000 S cm−1respectively. Small angle X-ray diffraction (SA-XRD) indicates that the oxidantincorporating the larger molecular weight co-polymer possesses orderedstructure and that this in turn helps “template” the PEDOT during filmformation. The structure and composition of the bottom (i.e. initial filmformation) and top (i.e. final film formation) PEDOT surfaces are studiedusing surface sensitive analytical techniques; small angle X-ray diffraction(SA-XRD), ultraviolet photoelectron spectroscopy (UPS), 2D grazing incidenceX-ray diffraction (2D-GIXD), metastable induced electron spectroscopy (MIES)and neutral impact collision ion scattering spectroscopy (NICISS). The resultsindicate that the increase in conductivity using the larger molecular weightco-polymer additive is due to the film having larger lamella- and π-stackingregions in addition to doping levels which remain unchanged throughoutfilm formation. These conclusions are further supported by results obtainedon a model PEDOT:Tosylate system using density functional theory (DFT)calculations.Read less <