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Inherently conducting polymers (ICPs) combine the electrical properties of metals and semiconductors with a polymer’s ability to flex and/or stretch. In general, polymers are relatively simple to synthesise, however, ICPs themselves have had limited uptake in consumer devices. This lack of uptake is in part related to the insolubility of many ICPs in common industrial solvents, and hence methods to manufacture them in a usable form have been problematic. Vapour phase polymerisation (VPP) is one method that provides a convenient route to producing thin films of both soluble and insoluble ICPs, and nanocomposites thereof. In this critical review the VPP process will be discussed from the fundamental viewpoint of the proposed polymerisation mechanism and the parameters affecting polymer growth for a range of different monomers (thiophene, 3-hexylthiophene, pyrrole, 3,4-ethylenedioxythiophene, etc .). Looking forward into the future, new areas of polymer design and fabrication using VPP will be discussed, such as the enhancement of ICPs through additives, and next generation device fabrication based upon VPP ICPs. [ABSTRACT FROM AUTHOR]

Abstract: Various issues still exist for electrochemical nitrite reduction to ammonia especially the significant overpotential and the formation of unwanted side products. In this work, we aim to develop an electrochemical method to facilitate the ammonia production from nitrite under ambient conditions and low overpotentials. Poly(3,4-ethylenedioxythiophene)-5,5′-(dithiophen-2-yl)-2,2′-bipyridine-Fe (PEDOT–BIPY–Fe) electrodes were prepared using a facile vapour phase polymerization method. In-situ electrochemical UV–vis results confirm the presence of the Fe complex in the electrode. The obtained electrodes show good charge transfer between the PEDOT and the Fe complex and was successfully used to reduce nitrite to ammonia. Ammonia was detected when the applied potential was only −0.4V (vs Ag/AgCl) and high yield was achieved when −0.5V (vs Ag/AgCl) or more negative potentials were applied. [Copyright &y& Elsevier]

Abstract: This study investigates the effects of blending two conducting polymers with the aim to form an alloy photo-electrocatalyst for water oxidation. Establishing a catalyst of this nature – one that is capable of reducing the overpotential of a given electrochemical reaction through exposure to light – has the potential to aid in the development of a cost-effective water-splitting process driven by sunlight. In this work, a multi-step oxidative vapour-phase polymerisation (VPP) process was used to create a polymer mixture. This was achieved by first polymerising a layer of poly(3,4-ethylenedioxythiophene) (PEDOT) onto a substrate before placing in a chamber filled with selected monomers, namely poly(thieno[3,2-b]thiophene) (PTT) or poly(dithieno[3,2-b:2′,3′-d]thiophene) (PDTT). This allowed the monomer to polymerise with the residual oxidant within the initial PEDOT to form an interpenetrating network. Spectroscopic, electrochemical and electrical characterisation revealed a certain level of spontaneous interaction between the conducting polymer species within the mixtures, while a photo-enhanced effect of the water oxidation reaction was observed upon illumination. [Copyright &y& Elsevier]

Highlights: [•] Triblock copolymers have been incorporated into polypyrrole films using VPP. [•] The PPy:Copolymer films are smoother and more uniform than PPy alone. [•] PPy:Copolymer films have relatively greater electrical and environmental stability. [•] Varying the copolymer amount yields subtle manipulation of the PPy bandgap. [Copyright &y& Elsevier]

Abstract: A novel strain sensor for the measurement of large strains has been developed. The strain sensor was fabricated on natural rubber substrate coated with a very thin layer of the conducting polymer, polypyrrole, using vapour phase polymerisation technique in a vacuum environment. This process involves depositing a layer of FeCl3 oxidant onto the natural rubber strips which is then exposed to pyrrole monomer vapour to produce a very thin layer of conducting polymer. Various deposition parameters were experimented to determine the optimal process leading to the best strain sensing performance. Pre-straining the rubber substrate prior to deposition resulted in better stability and consistency of the sensing performance. Oxygen plasma exposure of 200W for 40s produced the highest reduction in water contact angle on the rubber''s surface to improve the hydrophilicity without sacrificing the rubber''s elasticity and flexibility. High concentration of FeCl3 oxidant prove beneficial for the polymer coating to form as well as having monomer pyrrole diluted in acetonitrile that formed the polymer coating with the best strain sensing performance. A gauge factor of up to 1.86 was achieved. The sensor has the potential to detect large mechanical strains. The developed strain sensor was successfully implemented on an air muscle where the extension and contraction of the muscle can be accurately controlled. It also has a capability to measure large bending strains and hence be used as a rotary sensor. [Copyright &y& Elsevier]

Abstract: Large-scale electrochromic devices were manufactured using vacuum vapour phase polymerised (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT). Homogeneous 3,4-ethylenedioxythiophene (EDOT) and water vapour distribution within the large 115L VPP chamber is paramount for the reproducible synthesis of high conductivity PEDOT thin films. Obtaining these conditions, however, was not trivial. The issue was resolved by synthesising PEDOT under vacuum, however, this altered the dynamics of the polymerisation process. As a result, surfactant addition, monomer and water vapour distribution, monomer and chamber temperature, and polymerisation times were all systematically investigated. Controlling these parameters has resulted in PEDOT with conductivity exceeding 1100S·cm−1, with a best of 1485S·cm−1, and electrochromic devices with an optical switch of Δ%Tx≥50%. The resulting high conductivity and optical range are due to long undisrupted PEDOT polymer chains coupled with low levels of oligomers within the matrix. [Copyright &y& Elsevier]

Abstract: A series of iron(III) alkylbenzenesulfonate (ABS) salts were prepared by the reaction of ferric hydroxide, Fe(OH)3·xH2O, with a variety of aromatic sulfonic acids. The products were characterised by microanalysis and FTIR spectroscopy. The microanalysis data generated indicated that three of the salts were not mononuclear iron(III) compounds and were of the formula [(OH2)5Fe–O–Fe(OH2)5][C2H5C6H4SO3]4, [(OH2)5Fe–O–Fe(OH2)5][CH3C6H4SO3]4·2H2O and [(OH2)5Fe–O–Fe(OH2)5][CH3C6H4SO3]4. Some degree of condensation or cross-linking of Fe(III) centres into hydrolytic oligomers had occurred. The X-ray crystal structure of the Fe(III) toluenesulfonate salt established the formula of an oxo-centred, binuclear complex [(H2O)5Fe(μ-O)Fe(OH2)5]4+. Vapour phase polymerisation (VPP) of pyrrole monomer was carried out using iron(III) benzenesulfonate, p-ethylbenzenesulfonate, dodecylbenzenesulfonate and p-toluenesulfonate. As the chain length of the Fe(III) alkylbenzenesulfonates increased it was found that the film forming ability of the polypyrrole was enhanced, probably as a result of a decrease in polymer chain interaction resulting from increased free volume between polymer chains. Variations in the conductivity of the polypyrrole films was observed when Fe(III) p-toluenesulfonate salts obtained from different sources (two commercial samples and one synthesised in our laboratories) were used as the oxidant. Films deposited using these oxidants generally exhibited higher conductivity than those formed using the Fe(III) p-ethylbenzenesulfonate and Fe(III) p-dodecylbenzenesulfonate salts. [Copyright &y& Elsevier]

Abstract: Transparent electrodes based on PEDOT were prepared using a variety of techniques suitable for large area applications from 3,4-ethylenedioxythiophene (EDT) and Fe(III)-tosylate. High conductivities were obtained (∼20Ω−1) with moderate transmission in the UV-visible range 350–600nm. We subsequently demonstrate the application of PEDOT electrodes to flexible polyethyleneterphthalate plastic substrates (PET) prepared by this procedure for polymer photovoltaic devices with active areas of 4.2cm2 using a 1:4 w/w mixture of MEHPPV and PCBM. We obtain typical efficiencies of 0.2% under simulated sunlight (AM1.5 at 1000Wm−2). [Copyright &y& Elsevier]

Abstract: Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings, and because its reaction products can be removed efficiently after the formation of the composite. Several combinations of polymers are demonstrated, and the versatility of the proposed method allows extensions to a wide range of conjugated polymers. The IPNs show optical and electrochemical characteristics, which are sums of the characteristics from the participating conducting polymers. [Copyright &y& Elsevier]