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The precursor routes to obtain high-molecular weight poly(p-phenylene vinylene)s (PPVs) are reviewed with respect to their applicability towards specific synthesis goals and materials as well as their structural integrity.

A technique for the continuous on-line monitoring of polymerization processes by electrospray ionization mass spectrometry (ESI-MS) is presented via coupling with a commercial microreactor system. The potential is demonstrated by monitoring polymerizations in real time under synthesis conditions. Furthermore, a single acrylate monomer insertion into a oligo-RAFT agent, as used in the synthesis of monodisperse sequence controlled materials, was optimized by on-line screening of reaction conditions.

Well‐defined acrylate RAFT polymers and multiblock‐copolymers have been synthesized via the use of a continuous‐flow microreactor, in which polymerizations could be executed in 5−20 min reaction time. First, Poly(n‐butyl acrylate) (PnBuA) was synthesized in the micro‐flowreactor by using two different trithiocarbonate RAFT agents. Reaction time and reaction temperature were optimized and collected samples were directly studied with NMR, SEC and ESI‐MS to determine conversion, molar mass and end group fidelity. Using the continuous flow technique, highly reproducible and fast polymerizations yielded quantitatively functionalized PnBuA in a very facile and efficient manner. One batch of RAFT acrylate polymer with a molar mass of 1100 g mol−1 and excellent end group fidelity was employed as a macro‐RAFT agent for the subsequent copolymerization with different acrylate monomers (2‐ethylhexyl acrylate, t‐butyl acrylate, n‐butyl acrylate). Using this procedure, a sequential multiblock‐copolymer (Mn = 31,200 g mol−1, PDI = 1.46) consisting of five consecutive acrylate blocks was synthesized. This study clearly demonstrates the potential of using a continuous‐flow microreactor for subsequent RAFT polymerizations towards well‐defined multiblock‐copolymers. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 2366–2374

An effective procedure to synthesize sequence controlled oligoacrylates with up to four monomer insertions via the RAFT technique is presented. Two different sets of oligomers with a preferred monomer order were synthesized. Recycling SEC allowed for facile and automated purification of the monodisperse sequence-controlled materials.

Photo-induced copper-mediated radical polymerization is used to synthesize monodisperse sequence defined acrylate oligomers via consecutive single unit monomer insertion reactions and intermediate purification of the compounds by column or preparative recycling size exclusion chromatography.

A kinetic Monte Carlo modeling study is presented for precursor polymer formation via the sulfinyl precursor route. The premonomer, 1-(chloromethyl)-4-[(n-octylsulfinyl)methyl]benzene, is subjected to a NatBuO induced 1,6-elimination in sBuOH yielding the actual p-quinodimethane monomer that leads, via a radical polymerization, to the precursor polymer. The kinetic Monte Carlo model is able to predict the experimental trends in yield, mass averaged molar mass and structural defect content. The effect of radical recombination and cyclization is modeled and found to be negligible. The effect of the initial base and premonomer concentration on the polymer properties is investigated. Simulation results indicate a maximum in the polymer yield and chain length for initial [base]/[premonomer] = 1 and that the molecular properties of the precursor polymers can be varied by as much as 50% by an appropriate choice of initial [base]/[premonomer]. The kinetic Monte Carlo model is used to determine reaction conditions to achieve targeted polymer yields, chain lengths and structural defect contents.

To improve the thermal stability of polymer:fullerene bulk heterojunction solar cells, a new polymer, poly[2-methoxy-5-(2 0 -phenylethoxy)-1,4phenylenevinylene] (MPE-PPV), has been designed and synthesized, which showed an increased glass transition temperature (T g ) of 111 °C. The thermal characteristics and phase behavior of MPE-PPV:[6,6]-phenyl C 61 -butyric acid methyl ester ([60]PCBM) blends were investigated by means of modulated temperature differential scanning calorimetry and rapid heatingÀcooling calorimetry. The thermal stability of MPE-PPV:[60]PCBM solar cells was compared with devices based on the reference MDMO-PPV material with a T g of 45 °C. Monitoring of the photo-currentÀvoltage characteristics at elevated temperatures revealed that the use of high-T g MPE-PPV resulted in a substantial improvement of the thermal stability of the solar cells. Furthermore, a systematic transmission electron microscope study of the active polymer:fullerene layer at elevated temperatures likewise demonstrated a more stable morphology for the MPE-PPV:[60]PCBM blend. Both observations indicate that the use of high-T g MPE-PPV as donor material leads to a reduced free movement of the fullerene molecules within the active layer of the photovoltaic device. Finally, optimization of the PPV:fullerene solar cells revealed that for both types of devices the use of [6,6]-phenyl C 71 -butyric acid methyl ester ([70]PCBM) resulted in a substantial increase of current density and power conversion efficiency, up to 3.0% for MDMO-PPV:[70]PCBM and 2.3% for MPE-PPV:[70]PCBM.