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Although propylene/propane separation remains a challenge for industrial processes, carbon molecular sieve membranes (CMSMs) have the potential to replace traditional separation methods. A high molecular weight crosslinkable polyimide was utilized to fabricate CMSMs, which showed pure gas permeabilities in excess of 400 barrers with propylene/propane selectivities as high as 25. Mixed gas (C3H8:C3H6 50:50) measurements yielded a propylene permeability of 257 barrers and a selectivity of 20. CMSMs from thermally precrosslinked polymer precursors demonstrated a 98% propylene permeability retention after aging for 20 days under vacuum. Active gas flow conditions resulted in slightly lower permeability retention (92.5%) after 15 days of testing.

For the first time, porous organic polymers (POPs) based on the smallest buckybowl, corannulene (BB-POPs) have been synthesized. Three POPs were synthesised via Sonogashira co-polymerization of 1,2,5,6-tetrabromocorannulene and alkyne linkers. BB-POP-3 exhibits the highest surface area (SABET = 560 m2 g−1) and CO2 adsorption of 11.7 wt%, while they retain the redox properties of corannulene.

Polymer blends yield carbon materials with superior performances for supercapacitor applications since blending can lead to controlled and fine pore architectures. In this study, a supercapacitor electrode material derived from an immiscible polymer blend comprising polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) was investigated. PAN was used as the carbonizing polymer while PMMA was used as the sacrificial polymer. The polymer blend solutions in DMF were electrospun to obtain freestanding nanofiber mats. The resulting mat was carbonized and activated by CO2 at 1000 °C to obtain porous carbon nanofibers (CNFs), as PAN converts to carbon and the sacrificial polymer decomposes creating pores. We demonstrated that the pore sizes can be tuned by varying the amount of PMMA loading in the blend compositions. PAN : PMMA (95 : 5), was found to be the optimum blend composition, affording the highest surface area of 2419 m2 g−1, higher degree of graphitization, higher carbon yield and lower charge transfer resistance among the blend compositions studied. Furthermore, the PAN : PMMA (95 : 5) CNFs showed the highest capacitance of 140 F g−1 and energy densities of 67 W h kg−1 at 3.5 V and 101 W h kg−1 at 4 V in an ionic electrolyte (EMITFSI) and also showed good cycling stability with 85% capacitance retention after 1000 cycles.

This study reports the fabrication of a highly hydrogen selective cross-linked polymer skin on a highly permeable mixed matrix membrane. Selective polymer skins were prepared by spin coating a thin layer of 6FDA-durene polymer onto ZIF-8/6FDA-durene mixed matrix membranes followed by subsequent cross-linking of the 6FDA-durene layer with ethylene diamine (EDA) vapor. Resultant membrane yielded significantly high gas pair selectivities for the separation of H2/CO2, H2/N2 and H2/CH4 of 29, 341, and 278, respectively, while also maintaining a high hydrogen permeability of 500 Barrers. The superior separation performances of this system surpass the current permeability–selectivity tradeoff limits (Robeson 2008 upper bound) for H2/CO2, H2/N2, and H2/CH4 separations. The present work elucidates the potential of fabricating a highly selective layer (thin skin) on a highly permeable membrane to obtain high permeability and high selectivity simultaneously.

The MIL-53 metal–organic framework (MOF) is known to change reversibly from an open-pore framework (MIL-53-ht) to a closed-pore framework (MIL-53-lt) depending on the temperature, pressure, or guest molecules absorbed. Three frameworks of the additive, MIL-53-as synthesized (MIL-53-as), MIL-53-ht, and MIL-53-lt, were prepared, characterized, and combined with Matrimid® to form mixed-matrix membranes (MMMs) for gas separations. The MIL-53-ht/Matrimid® MMMs exhibited higher values of permeability compared to Matrimid® as well as an increased CO 2 /CH 4 selectivity suggesting that the open-pore MIL-53 framework was maintained in the polymer matrix. In addition to higher permeability values, MIL-53-as/Matrimid® MMMs showed higher selectivity for gas pairs with kinetic diameters differing by ⩾0.5 A, including H 2 /O 2 , CO 2 /CH 4 , H 2 /CH 4 , and H 2 /N 2 , suggesting the presence of excess benzene dicarboxylic acid molecules within the pores that reduced its diameter enabling the material to discriminate between smaller and larger gases. MIL-53-lt did not retain its closed-pore form in the MMM. Rather, it irreversibly converted to the open-pore form (MIL-53-ht) due to the exchange of water present in the MIL-53 pores with chloroform solvent molecules during membrane casting and to pore penetration and confinement by Matrimid® polymer chains. This finding, that a polymer matrix stabilizes a MOF pore architecture within an MMM, is significant in that the desired selectivity of a MOF-MMM system may be achievable.

Crystals of highly soluble metal-organic polyhedra 18 (MOP-18) were synthesized and used as additives in Matrimid® 5218 to form mixed-matrix membranes. The MOP-18 linker was functionalized with long alkyl chains to help the crystals dissolve in common organic solvents. Scanning electron microscopy images revealed that the MOP-18 molecules do not aggregate into large particles even at loadings as high as 80 wt%, and the absence of polymer veins or polymer rigidification at the MOP-18/polymer interface was attributed to the improved dispersion of the MOP-18 molecules in the polymer matrix. The increase in the modulus of the membranes from 1.4 GPa for the pure polymer to 2.4 GPa upon incorporation of MOP-18 was attributed to the strong affinity of the polymer chains for the alkyl chains of MOP-18. Gas permeation results showed that the membranes became more permeable as the temperature was increased from 35 to 70 °C and that CO2 plasticization, which occurred at 35 °C and 8 bar, was minimized when the membranes were heated to 70 °C owing to an increase in the plasticization pressure to 21 bar. At 70 °C, the H2/CO2 selectivity remained constant when the transmembrane pressure was increased from 3 to 30 bar. The permeability and solubility data at high pressure and high temperature showed that the pore, core, and alkyl chains of MOP-18 introduced new sorption sites that significantly affected the gas transport properties of the membranes. The results also demonstrated that the MOP-18/polymer interface was mechanically stable at high pressure.

We have developed a novel approach for compatibilizing immiscible polymer blends using metal organic frameworks (MOFs). For the first time we demonstrated that the droplet diameter of the dispersed phase in a 1:1 immiscible polymer blend composed of 6FDA-DAM:DABA [copolymer of 4,4-hexafluoroisopropylidene diphthalic anhydride (6FDA), 2,4,6-trimethyl-1,3-phenylenediamine and 3,5-diaminobenzoic acid (DABA)], and polybenzimidazole (PBI), is dramatically reduced obtaining a uniform microstructure with the incorporation of as low as 5% (w/w) of the zeolitic imidazolate framework-8 (ZIF-8). This indicates a large improvement in the compatibility of the immiscible polymers with the inclusion of ZIF-8. As the ZIF-8 loading was further increased to 10% (w/w), the droplet diameter further decreased resulting in even higher compatibility. The compatibilizing effect can be attributed to a reduction in the interfacial energy of the immiscible polymers due to the interfacial localization of ZIF-8. This MOF based compatibilization of immiscible polymer blends can open up opportunities for the combination of different properties of polymers in membrane-based separations and in more applications.

The demand for cost-efficient separations requires membranes with high gas flux and high selectivity which opens the path for further improvements. Mixed matrix membranes (MMMs) made from 33.3 wt % ZIF-8 in 6FDA-durene were tested at 35 °C and 3.5 atm. At 33.3 wt % loading of ZIF-8, H2, N2, O2, and CH4 gas permeabilities increased approximately 400%. Cross-linking the surface of this MMM, by reacting with ethylenediamine vapor, yielded a 10-fold increase in H2/CO2, H2/N2, and H2/CH4 selectivities with respect to 6FDA-durene, preserving 55% of the H2 permeability of 6FDA-durene. The permselective properties of the cross-linked skin of the MMM fall above the most recent permeability–selectivity trade-off lines (2008 Robeson upper bounds) for H2/CO2, H2/N2, and H2/CH4 separations. To the best of our knowledge, this is the first example of a cross-linked ZIF/polymer MMM for gas separation.

A phase-separated morphology, as observed in block copolymers, for proton exchange materials (PEM) is expected to result in improved PEM fuel cell performance. Blending hydrophilic and hydrophobic polymers provides an easier route to this phase-separated morphology especially for an otherwise difficult block copolymer synthesis. Blends of hydrophilic and hydrophobic perfluorocyclobutyl (PFCB) polymers were prepared and characterized as PEMFC membranes. The [2 π +2 π ] cyclodimerization of 4,4'-bis(trifluorovinyloxy)biphenyl and 4,4'-sulfonyl-bis(trifluorovinyloxy)biphenyl monomers afforded the hydrophobic homopolymers biphenyl perfluorocyclobutyl (BP-PFCB) and sulfonyl-bridged biphenyl perfluorocyclobutyl (SO 2 -PFCB), respectively. The hydrophilic homopolymer was prepared by post-sulfonation of the BP-PFCB using chlorosulfonic acid and thionyl chloride, yielding sulfonated biphenyl (sBP-PFCB) polymer. Blends of sBP-PFCB with SO 2 -PFCB and BP-PFCB were prepared in 1:1 mol ratios, resulting in higher ion exchange capacity (IEC) values and reduced membrane swelling by water when compared to Nafion ® . The pure hydrophilic sBP-PFCB polymer showed a 2.40 mmol/g IEC, while its 1:1 mol ratio blends with BP-PFCB and SO 2 -PFCB, gave IECs of 1.36 and 1.37 mmol/g, respectively, which are over 1.5× that of Nafion ®' s. Blending these polymers combined the mechanically and thermally stable PFCB backbone with the highly acidic sulfonated PFCB and displayed nanophase-separated morphologies without the challenge of controlling polydispersities. Proton conductivity of 6 and 8×10 −2 S/cm for the sBP-PFCB blend with BP-PFCB and SO 2 -PFCB respectively, was achieved at 80° C and 100% relative humidity. Testing a 1:1 mol ratio of sBP- and SO 2 -PFCB blend at ∼100° C and 50% relative humidity showed a higher proton conductivity of 1.5×10 −1 S/cm. These results confirm that the blends of hydrophilic (sulfonated) and hydrophobic PFCB polymers can be promising materials for fuel cell membranes.

Thermoacoustic performance of thin freestanding sheets of carbonized poly(acrylonitrile) and polybenzimidazole nanofibers are studied as promising candidates for thermophones. We analyze thermodynamic properties of sheets using transport parameters of single nanofibers and their aligned and randomly electrospun thin film assemblies. The electrical and thermal conductivities, thermal diffusivity, heat capacity, and infrared blackbody radiation are investigated to extract the heat exchange coefficient and enhance the energy conversion efficiency. Spectral and power dependencies of sound pressure in air are compared with carbon nanotube sheets and theoretical prediction. Despite lower thermoacoustic performance compared to that of CNT sheets, the mechanical strength and cost-effective production technology of thermophones make them very attractive for large-size sound projectors. The advantages of carbonized electrospun polymer nanofiber sheets are in the low frequency domain (1000 Hz), where the large thermal diffusion length diminishes the thermal inertia of thick (∼200 nm) nonbundled fibers and the high intrinsic thermal conductivity of fibers enhances the heat exchange coefficient. Applications of thermoacoustic projectors for loudspeakers, high power SONAR arrays, and sound cancellation are discussed.

Gas separation for industrial, energy, and environmental applications requires low energy consumption and small footprint technology to minimize operating and capital costs for the processing of large volumes of gases. Among the separation methods currently being used, like distillation, amine scrubbing, and pressure and temperature swing adsorption, membrane-based gas separation has the potential to meet these demands. The key component, the membrane, must then be engineered to allow for high gas flux, high selectivity, and chemical and mechanical stability at the operating conditions of feed composition, pressure, and temperature. Among the new type of membranes studied that show promising results are the inorganic-based and the metal-organic framework-based mixed-matrix membranes (MOF-MMMs). A MOF is a unique material that offers the possibility of tuning the porosity of a membrane by introducing diffusional channels and forming a compatible interface with the polymer. This review details the origins of these membranes and their evolution since the first inorganic/polymer and MOF/polymer MMMs were reported in the open literature. The most significant advancements made in terms of materials, properties, and testing conditions are described in a chronological fashion.

A novel symmetrical alkylsulfonyl-substituted poly(phenylenevinylene) derivative, poly [2,5-bis-(2'-ethylhexylsulfonyl)-1,4-phenylene)vinylene] (SO2EH-PPV), was synthesized via palladium-catalyzed Stille coupling, and its electronic and optical properties were investigated. The novel PPV derivative was characterized by NMR, UV-visible absorption, photoluminescence, gel permeation chromatography, infrared spectroscopy, and cyclic voltammetry (CV). The polymer with Mw of 27,800 and a polydispersity index of 2.6 is readily soluble in common organic solvents, such as THF, chloroform, and toluene. The fluorescence quantum yield of the polymer, determined against rhodamine 6G in dilute aqueous solutions, was 0.95. The HOMO and LUMO levels of SO2EH-PPV were calculated to be -6.0 and -3.61 eV, respectively. The results obtained by CV suggest that SO2EH-PPV is a strong electron acceptor polymer. Single layer stable polymer light-emitting diode devices with the configuration of (ITO/PEDOT:PSS/SO2EH-PPV polymer/Al) were fabricated exhibiting a green light emission.

In this study, we explore the effect of the dialkoxy and dithioalkoxy side chains on the benzo [1,2-b:4,5-b′]dithiophene (BDT) unit by comparing the O-BDT homopolymer (O-PBDT), S-BDT homopolymer (S-PBDT), and S-BDT-alt-O-BDT copolymer (SO-PBDT) by computational calculations and experimental results. The polymers were prepared by Pd-catalyzed Stille coupling. Additionally, hole mobility and film morphology were studied by fabricating organic field effect transistors (OFETs) and using TappingMode AFM, respectively. The photovoltaic properties of the polymers were measured from fabricated PSC devices. The replacement of the alkoxy (−OR) groups with thioalkoxy (−SR) groups lowered the HOMO energy level of the conjugated polymers from 5.31 to 5.41 eV, and consequently enhanced Voc, while still preserving the excellent properties offered by the BDT-based polymers. Especially, high Voc of 0.99 V was achieved from S-PBDT polymer based PSC with up to 4.0% of PCE, which is one of the highest efficiencies reported f...

Novel proton conducting composite membranes were synthesized by blending Nafion ® polymer with sulfonated organosilicon dendrimers (G3-S). Blending G3-S with Nafion resulted in stable, flexible membranes with loadings up to 10% by weight. The high amount of sulfonic acid groups on the dendrimer increased the ion exchange capacity and improved the water retention capability of the composite membranes with less swelling. The proton conductivity of the composite membranes was higher at all measured temperatures under both high and low relative humidity conditions, compared to pure Nafion ® . The proton conductivity of Nafion ® increased from 0.086 S/cm (at 80 °C at 100% relative humidity) for the pure polymer to 0.156 S/cm for the 10 wt% loading of dendrimer.

Single-particle fluorescence spectroelectrochemistry was used to investigate the electrochemical oxidation of isolated, immobilized particles of the conjugated polymers BEH-PPV and MEH-PPV at an indium tin oxide (ITO) electrode immersed in an electrolyte solution. Two types of particles were investigated: (i) polymer single molecules (SM) and (ii) nanoparticle (NP) aggregates of multiple polymer single molecules. For the BEH-PPV polymer, the observation of nearly identical lowest oxidation potentials for different SM in the ensemble is evidence for effective electrostatic screening by the surrounding electrolyte solution. A combination of Monte Carlo simulations and application of Poisson-Boltzmann solvers were used to model the charging of polymer single molecules and nanoparticles in the electrochemical environment. The results indicate that the penetration of electrolyte anions into the polymer nanoparticles is necessary to produce the observed narrow fluorescence quenching vs oxidation potential curves. Finally, fluorescence-lifetime single-molecule spectroelectrochemical (SMS-EC) data revealed that at low potential an excited state reduction process (i.e., electron transfer from ITO to the polymer) is probably the dominant fluorescence quenching process.

Poly(p-phenylenevinylene) (PPV) derivatives have long been studied because of their attractive opto- and electroluminescent properties and have potential applications for devices such as light-emitting diodes and photovoltaics. The ability to induce alignment of these PPV derivatives may lead to the enhancement of charge mobility and their efficiency. In this study, uniform nanofibers of poly[2,5-(2'-ethylhexyloxy)]-1,4-phenylenevinylene (BEH-PPV) have been fabricated through the method of electrospinning, and an induced alignment of the polymer fibers was observed through photoluminescence data. This study also focuses on the doping of these fibers with the fullerene derivative, 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)-C(61) (PCBM), to induce more incidence of donor/acceptor junctions. Composite fibers with up to a 1:2 weight ratio of PCBM/BEH-PPV have been fabricated and exhibited an ability to quench the photoluminescence of BEH-PPV, indicative of charge transfer.

Metal–organic framework 5 (MOF-5) nanocrystals with a high surface area (3000 m 2 /g) and high thermal stability (up to 400 °C) were synthesized and added to Matrimid ® to form mixed-matrix membranes for gas separations. Scanning electron microscopy (SEM) images of the membrane cross-sections revealed significant plastic deformation of the polymer matrix owing to the strong affinity between the MOF-5 and Matrimid ® . At 30% MOF-5 loading, the permeabilities of the gases tested increased 120% while the ideal selectivities remained constant compared to Matrimid ® . Residual gas analysis of permeates of gas blends with different mixture ratios revealed an increase in selectivity for CH 4 .

Mixed-matrix membranes were prepared from Matrimid® and mesoporous ZSM-5 nanoparticles containing crystalline ZSM-5. The ideal selectivity for H2/N2 separation increased from 79.6 for pure Matrimid® to 143 at 10% loading, while the selectivity of O2/N2 increased from 6.6 for pure Matrimid® to 10.4 at 20% loading. The ideal H2/CH4 separation factor increased from 83.3 to 169 at 20% loading. The results suggest that the mesopores of the ZSM-5 material provide good contact between the nanoparticles and the polymer, since the polymer chains can penetrate into the mesopores. The micropores of ZSM-5 crystals provide size and shape selectivity.

A microporous metal-organic framework Cu–4,4′-bipyridine–hexafluorosilicate (Cu–BPY–HFS), having a surface area of 2000 m2/g, was combined with Matrimid® polymer to form free standing films. The permeability properties of Cu–BPY–HFS–Matrimid® mixed-matrix membranes were tested for the pure gases H2, N2, O2, CH4, and CO2 and the gas mixtures CO2/CH4, H2/CO2 and CH4/N2. The ideal selectivity of CH4/N2 increased from 0.95 to 1.21, which suggests that Cu–BPY–HFS has a strong affinity towards CH4 and favors its permeation. The higher solubility of CH4 in the membranes leads to higher selectivity for CH4/N2. The enhanced CH4 transport is also apparent in the case of ideal selectivity for CO2/CH4 and H2/CH4. For CH4/N2 gas mixtures, the selectivity increased from 0.95 to 1.7. The Cu–BPY–HFS's affinity towards CH4, and its large surface area increased the solubility of CH4 in the mixed-matrix membranes, which led to higher selectivity towards CH4.

A carbon aerogel was prepared by carbonizing a resorcinol−formaldehyde polymer gel at 800 °C. Nitrogen adsorption shows the obtained carbon aerogel has both micropores (0.54 nm) and mesopores (2.14 nm). Matrimid mixed-matrix membranes containing the carbon aerogels were successfully prepared and evaluated for the permeation of H2, N2, O2, CH4, CO2, and gas mixtures. The ideal selectivity of H2/N2, CO2/CH4, and O2/N2 gas pairs increased from 79.6, 34.5, and 6.6 for pure Matrimid to 111, 47.8, and 9.1 at 20% loading, respectively. These results suggest that the polymer chains can penetrate the carbon mesopores to achieve good contact between the carbon aerogel and Matrimid, while the micropores may provide size and shape selectivity.

The process of electrospinning, which produces fibers in the nanometer to micron range under the influence of high voltages, has been widely studied to produce polymer and textile fibers. Mesoporous molecular sieve fibers have been produced in our lab, and this technique was extended to produce an interwoven mesh of polymer-molecular sieve composite fibers. The electroluminescent polymer MEH-PPV and molecular sieve SBA-15 were used to produce the composite fibers. An interesting aspect of these composites is that the fluorescence of MEH-PPV is blue shifted in the composites. The composites have been characterized by microscopy, vibrational spectroscopy, and fluorescence measurements.

Electrochromic devices composed of laminated polymer layers, as the working electrode, and vanadium pentoxide, as the counter electrode, were prepared and evaluated. Three different laminate systems were investigated using various combinations of poly(3,4-ethylenedioxythiophene), poly(N-methylpyrrole), and polyaniline as the active electrochromes. The color change of the laminate devices was measured using spectrocolorimetric techniques and analyzed using Commission Internationale de l'Eclairage 1931 (x, y)-chromaticity coordinates. The device's observed colors in their fully doped and dedoped states are found to be linearly dependent on the color coordinates of the two individual polymers that comprise the laminate.

The ability to tune colour constitutes an important goal in the design of electrochromic devices. The majority of single electrochromic materials, whether inorganic or organic have a very narrow spectral colour change, however. Complex colours such as browns and tans that mimic natural vegetation and soils are not inherent to these materials. We have explored several strategies to achieve these colours including the use of copolymers that contain two distinct moieties, blends of polymers that have different colour changes, laminating two different polymers on the working electrode, and using fine patterns of two different materials to confuse the eye. We have constructed solid state electrochromic devices using ITO/Mylar substrates, a solid polymer electrolyte, a V2O5 counterelectrode and working electrodes that were made via one of the four methods outlined above. The colour changes of these devices were measured using spectrocolourimetry conforming to the CIE standard. The colour changes observed were similar to those of natural vegetation and soils.

Self-assembled multilayers of the three modified cyclodextrins (hexakis(2,3-O-hexyl-6-deoxy-6-amino)-α-cyclodextrin (1), heptakis(2,3-O-hexyl-6-deoxy-6-amino)-β-cyclodextrin (2), and octakis(2,3-O-hexyl-6-deoxy-6-amino)-γ-cyclodextrin (3)) on bare gold, as well as on gold surfaces modified with mercaptopropionic (4) and mercaptooctanoic (5) acid, were investigated by cyclic voltammetric, contact angle, FT-IR, and quartz crystal microbalance measurements in neutral aqueous media. The level of organization of the aggregates formed by the three CD derivatives (1−3) on the negatively charged surface of the mercaptopropionic and mercaptooctanoic acid modified gold electrodes proved to be substantially better than that on bare gold electrodes. This finding suggests that although the amphiphilic character of compounds 1−3 can induce aggregation on a gold surface, the electrostatic interaction between the carboxylic acid groups and the positively charged cyclodextrins is the primary force leading to the formation...

Conjugated copolymers with fragments of 2,6-pyridylvinylene and 1,4-phenylenevinylene have been prepared by the Wittig reaction between the diphosphonium salt of 2,6-bis(chloromethyl)pyridine and terephthaldehyde or 2,5-dialkoxyterephthaldehydes. The protonation reaction of poly(1,4-phenylenevinylene)-co-(2,6-pyridylvinylene) with hydrochloric acid and the quaternization reaction of poly(2,5-dioctyloxy-1,4-phenylenevinylene)-co-(2,6-pyridylvinylene) with methyl triflate have been investigated by spectrophotometric and fluorescent methods. The absorption, excitation and fluorescence spectra of these copolymers as well as their corresponding model compounds were studied and compared. The photophysical properties of the investigated polymers suggest that these materials could be good candidates for the fabrication of efficient blue light-emitting diodes.

An instrument was built for the permeation testing of flat polymer membranes under pressures up to 3.0 MPa and temperatures up to 300 °C. The high pressure, high temperature cell uses aluminum tape and a graphite gasket to minimize the leak from the high pressure side to the low pressure side, making possible the permeability measurements of slow diffusing gases such as N2. A computer program developed on a LabVIEW platform fully controls the instrument and data acquisition. It incorporates algorithms to automatically adjust the downstream volume, repressurize the upstream volume, vent the downstream volume to prevent over pressurization, and change the temperature of the permeation cell. The percent relative standard deviation of the permeability measurements was

We report copolycondensation reactions of several benzimidazole-, benzoxazole- and diphenylanthracenyl-containing chromophores with m -phenylenediamine (MPD), isophthaloyl chloride (IPC) and bisphenol A (BPA) to form polyamides and polyesters. The absorbance and fluorescence spectra of the polymers were measured and the actual molar ratios of luminophoric and nonluminophoric moieties in their structures were determined by comparison to model compounds. Most copolymers showed intense blue fluorescence, from solution and film, with a maximum in the 410–515 nm range. The present results demonstrate that non-conjugated luminescent polymers, which are potentially useful for light-emitting diode applications, may be obtained by a one-state copolycondensation technique.

Membrane-based gas separation has attracted a great deal of attention recently due to the requirement for high purity gasses in industrial applications like fuel cells, and because of environment concerns, such as global warming. The current methods of cryogenic distillation and pressure swing adsorption are energy intensive and costly. Therefore, polymer membranes have emerged as a less energy intensive and cost effective candidate to separate gas mixtures. However, the use of polymeric membranes has a drawback known as the permeability-selectivity tradeoff. Many approaches have been used to overcome this limitation including the use of polymer blends. Polymer blending technology synergistically combines the favorable properties of different polymers like high gas permeability and high selectivity, which are difficult to attain with a single polymer. During polymer mixing, polymers tend to uncontrollably phase separate due to unfavorable thermodynamics, which limits the number of completely miscible polymer combinations for gas separations. Therefore, compatibilizers are used to control the phase separation and to obtain stable membrane morphologies, while improving the mechanical properties. In this review, we focus on immiscible polymer blends and the use of compatibilizers for gas separation applications.

The synthesis and spectroelectrochemistry of polycyclopenta[2,1-b;4,3-b′]dithiophen-4-(cyano,nonafluorobutylsulfonyl)-methylidene (PCNFBS), a low bandgap conducting polymer which is both p- and n-dopable, are reported. A model electrochromic device incorporating this polymer as both the anode and the cathode is demonstrated.

Bis (phenylsulfonyl) methane, nonafluorobutylsulfonylacetonitrile or heptadecafluorooctylsulfonyl acetonitrile could be condensed with the strained ketone cyclopenta [2,1-b; 4,3-b′] dithiophen-4-one ( 1 ) to afford the corresponding α, β unsaturated sulfones using a combination of a Grignard reagent of the methylene compound, TiCl 4 -activation of the ketone and N-methylmorpholine as base for the final deprotonation-elimination step.

Conducting polymers can be doped and dedoped rapidly to high charge density and as a result are potential active materials for use in electrochemical capacitors. We discuss three schemes by which conducting polymers can be utilized in electrochemical capacitors and in the third of these, which employs a conducting polymer that can be both n- and p-doped, high energy and power densities are demonstrated. Polythiophenes can be both n- and p-doped reversibly and we have tested a number of poly-3-arylthiophenes in order to achieve the best n-doping at thick polymer films. We have found that poly-3-(4-fluorophenyl)-thiophene, in a solution of 1 mol dm−3 tetramethylammonium trifluoromethanesulfonate in acetonitrile, can be n- and p-doped, both reversibly and to high charge density. Such key properties for high power, energy storage devices have not been demonstrated before with conducting polymer active materials. We propose that the improvement in polymer n-dopability that results from derivitization of thiophene with aryl substituents in the 3-position, is probably achieved thanks to electron transfer from the negatively charged polythiophene backbone to the aryl substituent. This proposal is discussed in the light of modeling information and of voltammetric data. Further supporting information is provided by electron microscopy, impedance spectroscopy and electrochemical quartz crystal microbalance results.

Bis (phenylsulfonyl) methane, nonafluorobutylsulfonylacetonitrile or heptadecafluorooctylsulfonyl acetonitrile could be condensed with the strained ketone cyclopenta [2,1-b; 4,3-b′] dithiophen-4-one ( 1 ) to afford the corresponding α, β unsaturated sulfones using a combination of a Grignard reagent of the methylene compound, TiCl 4 -activation of the ketone and N-methylmorpholine as base for the final deprotonation-elimination step.

α-Terthienyl and 2,5-di(2-thienyl)pyrrole, n-alkylated at the β-position of the central ring, have been oxidized electrochemically or chemically to afford electroactive polymers which were characterized by cyclic voltammetry, spectroelectrochemistry and FTi.r. These systems, which can be viewed as α-linked alternating copolymers of bithiophene with a 3-alkylthiophene or 3-alkylpyrrole, display superior effective degrees of conjugation compared with homopolymers of similarly substituted 3-alkylheteroaromatics. Chemically generated materials are soluble in a variety of organic solvents, but fail to produce coherent films when cast from these due to lower degrees of polymerization than similarly produced 3-alkylthiophene homopolymers. Electrogenerated polymers are insoluble despite apparently comparable degrees of polymerization as determined by FTi.r. end-group analysis. Oxidation potentials of the monomers are reduced in proportion to the number of alkyl substituents.

Self assembled synthetic opals composed of spheres with 200-1500nm diameters were infiltrated with poly[2-methoxy5-(20-ethylhexyloxy)-l,4- phenylenevinylene] (MEH-PPV) and Poly [(m-phenylenevinylene)-co- (2,5-dioctoxy-pphenylenevinylene)] (PmPV) which are luminescent polymers. The luminescence spectra of the polymers was blue shifted when infiltrated deep into the nano-scopic opal pores relative to the luminescence spectra from thick films of the bulk polymers. Inverse composite plastic and luminescent polymer opals were constructed resulting in a significant blue shift in the peek luminescence of MEH-PPV from 568nm for the bulk polymer to 520nm in the inverse opal structure. We found mat the majority of the blue shifting observed could be explained by the formation of isolated polymer strands within the opals. Silica spheres were coated with MEH-PPV, dispersed in H 2o and coated with polyelectrolytes which recharged and sterically stabilized the colloidal surfaces. Luminescence spectra from individual and selfassembled silica spheres coated with MEH-PPV were also blue shifted.

The photoluminescence (PL) spectra of dilute solution and single crystals of distyrylbenzene show unique temperature dependent vibronic structures. The characteristic single frequency progression at high temperatures is modulated by a low frequency progression series at low temperatures. None of the series side band modes corresponds to any of the distyrylbenzene Raman frequencies. We explain these PL properties using a time dependent model with temperature dependent damping, in which the many-mode system is effectively transformed to two- and then to a single "apparent" mode as damping increases., Comment: 4 pages, 3 figures

We report a nearly twofold increase of short circuit current: from Isc ∼ 10 mA/cm2 to Isc = 16–20 mA/cm2 in P3HT/PCBM solar cells (SC) employing freshly prepared regio-regular poly(3-hexylthiophene) (RR-P3HT) without special purification. The power conversion efficiency is enhanced to η≥ 4% as compared to our best η=3.8% in SC with commercial polymer despite the decreased filling factor (FF= 0.42, as compared to best FF = 0.59). We used our earlier found [1] procedures with optimal post heat treatment temperatures and time for our polymer SC. We also discovered a strong correlation between the device preparation procedures and performance. The optimal phase separation of PCBM and RR-P3HT into a bi-continuous network structure occurs after quite long solution stirring times (enhanced homogenization) and surprisingly very short annealing time at optimal temperature. We also found that the optimal concentration of PCBM in a RR-P3HT matrix is rather low, only c∼35 wt%, contrary to high c∼80 wt% in PPV based SC.

We have developed a novel method for the preparation of mesoporous molecular sieve fibers by electrospinning deposition. Non-woven fibers of all silica DAM-1 and SBA-15 as well as the TiO2, In(SnO2) and Nb2O5 analogs have been prepared by electrospinning. This involves subjecting a syringe charged with a precursor gel to 20 kV over a distance of 23 cm, which results in jet of molecular sieve fibers. Additionally, a mesh of polymer and molecular sieve fibers have been electrospun using multiple syringes. An unusual mesopore structure is observed where well ordered grains a re randomly oriented along the fiber. In some cases such as for PEI/SBA-15, free standing molecular sieve paper can generated.

We have employed mesoporous molecular sieves in polymer membranes in an effort to enhance the permselectivity. The principal advantage of these materials is that the polymer chains can penetrate the pores reducing the nonselective voids that are often observed with inorganic additives. In this study, we have prepared Matrimid® membranes with various loadings of the all silica molecular sieve DAM-1 (Dallas Amorphous Material) as well as DAM-1 functionalized with amines in the channel wall, to enhance the gas permeability characteristics of a high performance polymer. For all gases tested (N2, O2, CO2, CH4), the permeability increased in proportion to the wt % of the amine DAM-1 present in the membrane. The addition of the amine DAM-1 resulted in modest ideal O2/N2 permselectivity, while the ideal CO2/CH4 permselectivity values were >100, depending upon the moisture content of the feed. The ideal CO2/CH4 permselectivity values are among the highest for this type of composite membrane. Details of membrane fabrication as well as permeability and permselectivity results will be presented for a range of Matrimid®/molecular sieve composites.

An electroactive polymer with a bandgap of ≈0.8 eV has been obtained from the monomer 4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b′]dithiophene.

An electroactive polymer with a lowered band gap has been obtained from the monomer cyclopenta[2,1-b;3,4-b′]dithiophen-4-one.

A novel approach to tailor the electrochromic properties of polythiophenes utilizing a silyl bridge to form discrete electrochromes is described. The monomer bis[2-(5,2'- dithienyl)]dimethyl silane was chemically synthesized and electrochemically polymerized. Electrochromic properties of devices incorporating this polymer as active material were studied and analyzed following CIE L*a*b* formalism. This polymer exhibits a yellow to green electrochromism from neutral to oxidized state.

Poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene and copolymers with fragments of 1 ,4-phenylene , 1,4-naphthylene, 9, 10-anthrylene and model compounds is one of the most interesting polymers, which have a high third-order non-linearity optical activity. We have investigated spectral luminescent characteristics (absorption, excitation and fluorescence spectra) ofthis compounds. The quantum chemical calculation of electronic structure model compounds were carried out in an AM1, PM3 approximation. It was founded the relationship between the structure of polymer and its spectral -luminescent properties and shown that creation intramolecular hydrogen bond and intermolecular complexes such as excimer - dimer plays significant role in formation of electronic structure polymer and consequently their non-linearity optical activity.

We report the Wittig reaction of the diphosphonium salt of 2,6-bis(chloromethyl)pyridine with terephthaldehyde, 2.5- dioctyloxyterephthaldehyde, or 9,10-anthracenedicarbaldehyde to form conjugated copolymers with fragments of 2,6 - pyridylene and para-arylenevinylene. The protonation reaction of poly(para-arylenevinylene)-co-(meta- pyridylvinylene) with hydrochloric acid and the quaternization reaction of poly(2,5-dioctyloxy-1,4- phenylenevinylene)-co-(2,6-pyridylvinylene) with methyl triflate have been investigated by spectrophotometric and fluorescent methods. The absorption, excitation and fluorescence spectra of these copolymers as well as their corresponding model compounds were studied and compared. The photophysical properties of the investigated polymers suggest that these materials could be good candidates for the fabrication of efficient blue and green light-emitting diodes.

The use of membrane technology for gas separations offers significant thermodynamic and economic advantages over distillation processes. Target separations of importance to the coal and energy fields include N{sub 2}/O{sub 2}, H{sub 2}S/syngas and CO{sub 2}/CH{sub 4}. Current strategies for improving these separations are largely directed towards processable polymers with thin (< 500 {angstrom}) skins. Unfortunately most polymeric materials that provide commercially viable permeation rates exhibit poor selectivities and vice versa and there are inherent limitations in gas permeability/permselectivity for pure polymers. The strategy relies on modification of composite membranes, preferably in situ, to enhance the permselectivity while maintaining acceptable permeabilities. The composites consist of electroactive polymers (which can be switched from rubbery to glassy), filled with selective absorbents (zeolites) which are impregnated with metals or catalysts to effect facilitated transport. The project is multifaceted and involves the efforts of a polymer synthesis group, a microporous materials group, a microscopy group and a permeability measurements group, all working in concert. This final report summarizes the results of the efforts on the project.

The fourth quarter of continued to see progress on five fronts: (a) instrument development, (2) polymer synthesis, (3) membrane fabrication and microscopy, (4) composite membrane fabrication and (5) permeability measurements. We have examined zeolite-polymer composite membranes with different zeolite loadings (10%, 25% and 50% by weight) using light and scanning electron microscopies in order to determine particle size distribution and homogeneity of dispersion. The distribution of zeolite (NaX) particles was fairly uniform across the length and width and excellent across the thickness of the film. The NaX crystallites displayed a reasonably uniform size distribution ranging between 2--5 {mu}m and this was carried over into the composite films made with the lower loading levels indicating that aggregation during the casting process was not occurring. At the highest loadings some clustering of the zeolites was observed.

A new dialkylthio benzo[1,2-b:4,5-b']dithiophene (S-BDT) was designed and synthesized and the polymer S-PBDT was prepared by a Stille coupling reaction. A high open-circuit voltage (V(oc)) of up to 0.99 V was achieved in polymer solar cells with PCBM.

A linear polythiophene, poly[bis(5‘,2‘-bithiophene-2-yl)]dimethylsilane, which incorporates silyl bridges in the backbone was synthesized to tailor the electrochromic properties. Solid-state electrochromic devices comprised of this polymer as the active material were fabricated and were analyzed following CIE L*a*b* formalism. By limiting the effective conjugation in the polymer, its electrochromic properties were deliberately altered to produce a yellow to green color change from its neutral to oxidized state.

The synthesis of 2-phenylthieno[3,4-b]thiophene was carried out in two steps from 3,4-dibromothiophene and phenylacetylene. Electropolymerization of this monomer affords a novel low band gap (Egap) polymer that was characterized by cyclic voltammetry and electrochemistry. An Egap of ca. 0.85 eV was observed, which is among the lowest reported to date for any conductive polymer.