Electrical conductivity of polyblends of poly(1,4-phenylene vinylene) and poly(2,5-dimethoxy-1,4-phenylene vinylene)

Summary A series of polyblends of poly(1,4-phenylene vinylene), PPV, and poly(2,5-dimethoxy-1,4-phenylene vinylene), PDMPV, were prepared in film form from precursor polyblends of the respective sulfonium salt polymers, which were separately prepared from the respectivebis(sulfonium salt) monomers. The blend films were doped with I₂ at room temperature to obtain a wide range of electrical conductivities (10^–2 to 10²Scm^–1) depending on the blend composition. The higher the content of PDMPV in the blends the higher was the conductivity.     

Synthesis and Properties of PPV–Based (η<Superscript>6</Superscript>–Arene)Cr(CO)3–Containing Polymers Having Alkyldiphenylamine or Triarylamine in the Main Chain

Summary Novel poly(p–phenylenevinylene)–based (⁶–arene)Cr(CO)3–containing polymers including the alkyldiphenylamine or triarylamine units in the main chain were synthesized by the Homer–Wadsworth–Emmons coupling reaction. The structures of the polymers were confirmed by NMR and FT–IR spectra. The polymers were soluble in common organic solvents such as THF, CHCl₃, and CH₂Cl₂. The polymer showed interaction between the electron–withdrawing (⁶–arene)Cr(CO)³ unit and the unshared electron pair on the nitrogen atom along the polymer backbone.     

Highly functionalized polystyrene by direct metalation—carboxylation

Summary Polystyrene was directly metalated using 1:1 mixture of n-butyllithium (n-BuLi) and potassium-t-butoxide (t-BuOK) in cyclohexane/hexanes at ambient temperature. The metalated polymer on reaction with solid carbon dioxide followed by a metal-proton exchange gave a carboxylated polymer containing 6.38–6.57 mmol acid/g polymer which corresponds to the introduction of carboxyl groups on 94–97% of the repeat units of polystyrene.Based on ¹³C nMR spectra meta, para and ortho aromatic ring substitution was proposed. No detectable backbone carboxylation occurs. the distribution of carboxylated sites on the aromatic ring: 9% ortho, 58% meta and 33% para. Quantitative ¹³C NMR analyses indicates essentially quantitative functionalization.     

Acetylene-cyclopentene copolymers

Summary Cyclopentene (CP) and 7,8-bis(trifluoromethyl)tricyclo-[4,2,2,0^2,5]-deca-3,7,9-triene (p-A) were copolymerized. The copolymers were thermally converted to acetylene-cyclopentene copolymers ACP-13, ACP-11, and ACP-31 containing 60.3%, 48.3% and 39.4% of CP, respectively. Infrared spectroscopy showed the copolymers to have increasing sequence length of conjugated double bonds with increasing acetylene contents. The copolymers have only small amounts of unpaired spins which are only one-tenth to one-hundredth of that found in normal trans-poly(acetylene). The copolymers absorb large quantities of iodine, which on the basis of sp ²-carbon atoms are comparable to iodine doped poly(acetylene). Doped ACP-copolymers acquire some increase of conductivity up to 10^–4 ( cm)^–1 for ACP-31 copolymer and evacuation returned the materials to their insulating states even though the samples retained a few mole % of I₃ ^–. The results are attributed to low carrier concentration and mobility.     

Synthesis and characterization of alternating copolymers containing bipyridine and phenylene vinylene for fluorescent chemosensors

Alternating copolymers containing bipyridine and phenylene vinylene were synthesized through a Wittig condensation reaction of their corresponding diphosphonium salts and dialdehydes. The molecular weights of the resulting polymers were relatively low because of the low solubility in the reaction solvents. The optical properties of the polymers were substantially affected by the repeating units of phenylene vinylene. The absorption spectra of the copolymers in the solid state exhibited a bathochromic shift compared to those carried out in solution. The effective conjugation length could be extended with the addition of Cu²⁺, Ni²⁺, and Zn²⁺ ions into the polymer solutions in a 1 : 1 ratio of the bipyridine to the phenylene vinylene units. All of the polymer solutions behaved as a turn‐off fluorescent chemosensor upon the addition of a variety of the metal ions. The sensing behavior to various metal ions revealed that the polymers were highly sensitive to the Cu²⁺, Ni²⁺, and Zn²⁺ ions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42795.     

Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)furan]

Summary Poly[2,5-bis(dimethylsilyl)furan] (V), a copolymer with alternating furan and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)furan (II) with sodium metal dispersion in toluene. Lower molecular weight poly[2,5-bis(dimethylsilyl)furan] (IV) has been prepared by a similar condensation reaction with 2,5-bis(dimethylfluorosilyl)furan (III). IV and V have been characterized by ¹H, ¹³C and ²⁹Si NMR, IR, and UV spectroscopy as well as by GPC, TGA and elemental analysis. Photolysis of V in a benzene/methanol solution results in degradation of the polymer.     

Cationic ring-opening polymerization of spirophosphorane, 5-phenyl-1,4,6,9-tetraoxa-5-phosphaspiro[4,4]nonane

Summary This paper reports new cationic ring-opening polymerization of a spirophosphorane, 5-phenyl-1, 4, 6, 9-tetraoxa-5-phosphaspiro (4, 4) nonane, 1. The polymerization of 1. was induced by cationic initiators such as methyl trifluoromethanesulfonate (MeOTf), BF₃·OEt₂, and Et₃O⁺-BF₄ ^– to give polymer 2 consisting of two different units, 2a and 2b. During the reaction cyclic phosphonate 3 and 1,4-dioxane were simultaneously produced. The formation of unit 2b is considered to be due mainly to the cationic ring-opening polymerization of 3.     

Synthesis of highly conjugated poly(3,9-carbazolyleneethynylenearylene)s emitting variously colored fluorescence

Novel conjugated polymers P1–P7 containing 3,9-linked carbazole units in the main chain were synthesized by the polycondensation of 3-ethynyl-9-(4-ethynylphenyl)carbazole (EEPCz) and dihaloarenes, and their optical and electrical properties were studied. Polymers with weight-average molecular weights of 4100–48,000 were obtained in 24–92% yields by the Sonogashira coupling polycondensation in tetrahydrofuran (THF)/Et₃N at 30 or 50 °C for 48 h. All the polymers absorbed light around 350 nm. The polymers with electron-accepter units exhibited absorption bands originating from charge transfer. The polymers except the one containing azobenzenes emitted variously colored fluorescence with moderate quantum yields upon excitation at the absorption maxima. P1–P3 were oxidized around 0.6 V, and then reduced around 0.5 V. The conductivity of P3 was 1.1 × 10⁻¹⁴ S/cm at 10³ V/cm.     

Synthesis and characterization of highly fluorescent phenylene vinylene containing perfluorocyclobutyl (PFCB) aromatic ether polymers

4-(Trifluorovinyloxy)benzaldehyde was treated under Wittig conditions with 4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) to form 1,4-bis(2′-(4-trifluorovinyloxyphenyl)ethenyl)-2,5-dihexyloxybenzene, a novel phenylene vinylene-bistrifluorovinyl ether monomer. Cyclopolymerization afforded an insoluble, non-luminescent material likely due to cross-addition reactions between phenylene vinylene olefin and trifluorovinyl ether (TFVE). However, 1,2-bis(4-formylphenoxy)hexafluorocyclobutane was polymerized with 1,4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) and 1-methoxy-4-(2-ethylhexyloxy)-2,5-xylenebis(triphenylphosphoniumbromide) under Wittig conditions to yield two novel poly(perfluorocyclobutyl-co-phenylene vinylene) polymers. The polymers are of moderate molecular weight (8600-8700 M_n), show excellent thermal stability (T_d = 390-405 °C), and are readily soluble in common organic solvents. The materials are highly fluorescent in both solution and thin film with solution quantum yields of 68 and 71%.     

Synthesis of polymers with benzo-13-crown-4 and benzo-9-crown-3 units via cyclopolymerization

Summary Polymers containing crown ether units were synthesized by cyclopolymerization of divinyl and diepoxide monomers. These are 1,2-bis-(2-ethenyloxyethoxy)-benzene (1) and 1,2-bis-(2,3-epoxypropyl)-benzene (3) producing polymers with 13 and 9-membered rings 4 and 5, respectively. Both the monomers and polymers were characterized by IR, ¹H NMR and ¹³C NMR spectroscopy. Finally, the polymers were contacted with an aqueous solution of lithium chloride.     

Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)thiophene]

Summary Poly[2,5-bis(dimethylsilyl)thiophene] (I), a copolymer with alternating thiophene and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)thiophene (IV) with sodium metal in toluene. I has been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, UV, GPC, TGA and elemental analysis. The photolysis of I in benzene/methanol solution results in degradation of the polymer. The structure of the photoproducts and possible mechanisms for their formation are discussed.     

Synthesis and characterization of poly(fluorene vinylene) copolymers containing thienylene–vinylene units

Narrow‐band‐gap 2,5‐thienylene‐divinylene (ThV) units were incorporated into the poly(fluorene vinylene) backbone via a Gilch reaction as an energy trap with various feed ratios; this yielded pronounced changes in the electrochemical and optical properties of the material. The energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the polymers {poly(9,9‐di‐iso‐octylfluorene vinylene) [poly(fluorene vinylene‐co‐thiophene vinylene (FV))], C1, and C2 } were estimated to be ?5.53 to ?5.10 eV and ?2.98 to ?2.84 eV, respectively, by cyclic voltammetry measurements. In comparison with poly(FV), the HOMO energy levels of polymers poly(fluorene vinylene‐co‐thiophene vinylene (FV) (90 : 10) ( C1 ) and poly(fluorene vinylene‐co‐thiophene vinylene (FV) (80 : 20) ( C2 ) were significantly increased, but their LUMO energy levels were slightly decreased. The optical properties were investigated by absorption and emission spectra of the polymers. The good spectral overlap between the emission of poly(FV) and the absorption of polymers C1 and C2 revealed a sufficient energy transfer from the majority of 9,9‐di‐iso‐octylfluorene vinylene units to the minority of ThV units. The reduction of self‐absorption losses of polymers C1 and C2 due to spectral separation caused by the incorporation of ThV units could be indirectly confirmed by nonlinear optical (NLO) properties. The result of the NLO properties of the polymers showed that the third‐order NLO coefficients of poly(FV), C1, and C2 were 8.1 × 10^?10, 1.35 × 10^?9, and 1.51 × 10^?9 esu, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Lithium secondary cells using LiX (X=ClO4, BF4) as electrolyte and poly(2,5-pyrrolylene) and poly(2,5-thienylene) as materials for positive electrodes

Repeated charge-discharge cycles of lithium secondary cells using poly(2,5-pyrrolylene) and poly(2,5-thienylene) on carbon fibre plates as the materials for positive electrodes have been tested. When the Li|LiBF₄|poly(2,5-pyrrolylene) secondary cell is charged and discharged at 0.1 mA cm^–2, it gives 91% current efficiency and 70% energy efficiency with an average discharging voltage of 2.75 V at the 9th charge-discharge cycle. This secondary cell has a theoretical energy density of 135 kW kg^–1 based on the energy stored and the weights of poly(2,5-pyrrolylene) and the active materials. The Li|LiClO₄|poly(2,5-thienylene) secondary cells show somewhat lower current efficiency and energy efficiency at the 9th charge-discharge cycle. The lithium cells using the polymers are rechargeable more than 50 times, but after about 50 cycles considerable lowering of the current efficiency and energy efficiency of the cells is observed, presumably due to degradation of the polymer.     

Electron donors in carbocationic polymerization

Summary Low molecular weight (¯M_n 900–5000) narrow molecular weight distribution (MWD; ¯M_w/M_n = 1.1–1.2)tert.-chlorine telechelic polyisobutylenes (PIBs) have been synthesized by the use of thetrans-2,5-dimethyl-2,5-diacetoxy-3-hexene (DiOAcDMeH₆)/BCl₃ initiating system in the presence of the electron donor (ED) dimethyl sulfoxide (DMSO) in methyl chloride diluent at –30°C. The living character of the polymerization was demonstrated by linear M_n versus W_p (weight of polymer) plots starting at the origin with the slope of 1/[I_o] (where [I_o] = initiator concentration). DMSO reduces the overall rate of polymerization, however, it increases the initiator efficiency (I_eff) to 100%. The number averagetert.-chlorine end functionality is -F_n=1.97±0.04, by¹H NMR spectroscopy. Polymerization mechanistic details are discussed. This is the first time narrow MWDtert.-chlorine telechelic PIB has been prepared close to the reflux temperature of methyl chloride.Paper XXVII in the series on Living Carbocationic Polymerization. For paper XXVI see Kaszas et al., J. Macromol. Sci. Chem. to appear (1989)     

Luminescent π-conjugated poly(aryleneethynylene)s consisting of plural aromatic units: Preparation and systematic studies on their optical properties

A series of π-conjugated poly(aryleneethynylene)s (PAEs) containing two or three different arylene units in the main chain have been prepared by palladium-catalyzed coupling reactions. The PAEs consist of 2,5-dihexyloxy-1,4-phenylene diethynylene (–CC–C₆H₂(OC₆H₁₃)₂-p-CC–; C₆H₁₃ = hexyl) units with alternating arylene (–Ar–) units. Various kinds of arylenes, including 9,10-dihydrophenanthrene-2,7-diyl (Phen), pyridine-2,5-diyl (Py), thiophene-2,5-diyl (Th), anthracene-9,10-diyl (Ant), and 2,1,3-benzothiadiazole-4,7-diyl (BTdz), are used as the –Ar– units. The obtained PAEs were soluble in organic solvents by virtue of the attached hexyloxy side chains, and were characterized by NMR, IR, GPC, and UV–vis absorption and photoluminescence (PL) spectroscopy. The cooperation of different polymer segments induces variations in the electronic structure of the PAEs that show π–π* absorption peaks in the range of 380–530 nm and PL emission peaks in the range of 430–610 nm with quantum yields of 5–55% in their solutions. The UV–vis and PL peaks of the PAEs shifted to a longer wavelength in films and in colloidal solutions, indicating the occurrence of intermolecular electronic interactions by aggregation. In Ant-containing PAEs, the PL of the polymer chain was entirely replaced with a red-shifted PL emission assignable to the Ant segments due to intramolecular energy transfer.     

The electrical conductivity properties and structures of substituted poly(phenylene sulphides), synthesized from phenols and sulphur

Summary We have synthesized polyphenylenesulphides, using phenols, xylenes, sulphur and halogens as starting materials. The substituted and partly branched polyphenylenesulphides obtained have been doped with iodine (I₂). The structures have been investigated by elemental analyses, IR, NMR and GPC. The electrical conductivities of these products were rather low in the region of 10^–6–10^–11 Scm^–1. Higher conductivity values were observed for the polymers containing methoxy- or acetyl-substituents compared with those containing hydroxyl groups. It is suggested that this depends, at least partly, on the absence of hydrogen bonds between the sulphur atoms and the hydroxyl groups. As was expected molecular weight also had the effect of increasing the conductivity values observed.     

Synthesis and characterization of polymers derived from selenophene

The synthesis of poly(2,5‐selenophen‐oxo‐1,4‐phenylen‐selenide‐1,4‐phenylene‐oxo) (I) and poly(2,5‐selenophen‐oxo‐1,4‐phenylen‐diselenide‐1,4‐phenylen‐oxo) (II) by reaction of 2,5‐bis(1,4‐bromo‐phenylen‐oxo‐)‐selenophene with sodium selenide or diselenide, respectively, using dimethylformamide as solvent, is described. Both monomers and polymers were characterized by elemental analysis, melting point, and FTIR spectroscopy. Polymers I and II were doped with iodine and SbF₅ and characterized by SEM and XPS. Also, the conductivity and the T_g values were determined. For both polymers the best doping agent was iodine, although polymer II always presented higher conductivity, reaching values of about 6 · 10^?9 S · cm^?1. The T_g values suggest a likely crosslinking of the chains in polymer II when doped with SbF₅. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2019–2026, 2001     

New soluble π-conjugated polymers containing 2-diisopropylamino-1,3,5-triazine unit: synthesis,characterization and optical properties

A new type of π-conjugated polymers containing 2-diisopropylamino-1,3,5-triazine were prepared via Sonogashira or Suzuki coupling reaction. The structures of the polymers were performed by FT-IR, ¹H-NMR, UV–vis spectroscopy, photoluminescence spectroscopy, gel permeation chromatography, thermal analysis and X-ray diffraction analysis. These derived polymers were soluble in common organic solvents such as tetrahydrofuran, chloroform, toluene, and showed good thermal stability. Polymers containing 1,4-diethynyl-2,5-bis(dialkoxy)benzene unit in polymer main chain emitted blue-green light in solution phase under UV light irradiation except with polymer containing 9,9-dioctylfluorene(blue light). Acidochromic behaviors of polymers were studied in CHCl₃-CF₃COOH mixtures. 9,9-Dioctylfluorene-containing polymer displayed better acidochromic property and linear relationship between absorbance and concentration with the concentration of CF₃COOH from 5.384?×?10^?4 to 26.92?×?10^?4 mol/L. Electrochemical behaviors of polymers depicted p-doping and some hole-transporting properties. XRD results showed that polymers exhibited certain crystallinity.     

Polycondensation of squaric acid with N-alkylcarbazoles

Summary 1,2-Dihydroxycyclobutene-3,4-dione (squaric acid) was polycondensed with N-ethyl- and N-(1-butyl)carbazole in polyphosphoric acid to give polymers having 36–43% of 1,2-oriented squarate units. The polymers are insoluble in organic solvents or sulfuric acid. Condensation of 1,2-dichlorocyclobutene-3,4-dione (squaryl dichloride) with N-1-butyl-carbazole in nitrobenzene gave 100% of 1,2-oriented squarate units. This polymer is soluble in most organic solvents, and the molecular weight (¯Mw) is 1900 (DP=6). The electrical conductivity was low, <10^–9 (ohm cm)^–1, and did not increase on treatment with iodine.     

Alkyloxy-substituted liquid-crystalline aromatic copolyesters

Summary The synthesis and characterization of main chain liquid crystalline polyesters arising from 2,5-bispentyloxy substituted terephthalic aicd (3) and aromotic diols are described. 3 was prepared from diethyl 2,5-dihydroxyterephthalate and 1-bromopentane. The polyesters were prepared from 4,4-dihydroxybiphenyl (5), hydroquinone (6), 2,5-dimethyl hydroquinone (8) and the substituted terephthaloyl dichloride (4) in 1,1,2,2-terachloroethane. Their structures were characterized by ¹H-NMR, GPC and elemental analyses; their thermal behavior was studied by DSC measurements, microscopy under polarized light, and thermogravimetric analyses. The melting points are in the range of 130–280°C. All of them except of those with a high amount of 2,5-dimethyl hydroquinone (8) form a nematic phase above their melting point.