https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41142 2 V⁻¹ s⁻¹, respectively. Most intriguingly, a clear charge-carrier-polarity change is observed when the devices are measured under vacuum. The pDPF-DTF2 polymer exhibits a balanced ambipolar performance with the µ_h/µ_e ratio of 1.9, whereas pDPSe-DTF2 exhibits p-type dominated charge carrier transport properties with the µ_h/µ_e ratio of 26.7. Such a charge carrier transport change is due to the strong electron-donating nature of the selenophene. Furthermore, pDPPy-DTF2 with electron-withdrawing pyridine flanking units demonstrates unipolar n-type charge transport properties with an electron mobility as high as 0.20 cm2 V⁻¹ s⁻¹. Overall, this study demonstrates a simple yet effective approach to switch the charge carrier polarity in transistors by varying the electron affinity of flanking groups of the diketopyrrolopyrrole unit.]]> Wed 01 May 2024 15:47:56 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44487 co-2-(diethylamino)ethyl methacrylate) [P(MEO₂MA-co-DEA)] 80:20 mol % copolymer brushes were synthesized on planar silica substrates via surface-initiated activators continuously regenerated via electron transfer atom transfer radical polymerization. Brush thickness was sensitive to changes in pH and temperature as monitored with ellipsometry. At low pH, the brush is charged and swollen, while at high pH, the brush is uncharged and more collapsed. Clear thermoresponsive behavior is also observed with the brush more swollen at low temperatures compared to high temperatures at both high and low pH. Neutron reflectometry was used to determine the polymer volume fraction profiles (VFPs) at various pH values and temperatures. A region of lower polymer content, or a depletion region, near the substrate is present in all of the experimental polymer VFPs, and it is more pronounced at low pH (high charge) and less so at high pH (low charge). Polymer VFPs calculated through numerical self-consistent field theory suggest that enrichment of DEA monomers near the substrate results in the experimentally observed non-monotonic VFPs. Adsorption of DEA monomers to the substrate prior to initiation of polymerization could give rise to DEA segment-enriched region proximal to the substrate.]]> Fri 14 Oct 2022 08:57:26 AEDT ]]>