High Mass Materials Research Articles

Solubilizing Benzodifuranone-Based Conjugated Copolymers with Single-Oxygen-Containing Branched Side Chains.

Single-oxygen-containing branched side chains are designed and used to solubilize n-type copolymers consisting of BDF (benzodifuranone), isatin, and thiophene-based units. We present a simple synthetic approach to side chains with varying linker distances between the backbone and the branching point. The synthetic pathway is straightforward and modular and starts with commercially available reagents. The side chains give rise to excellent solubilities of BDF-thiophene copolymers of up to 90 mg/mL, while still being moderate in size (26-34 atoms large). The excellent solubility furthermore allows high molar mass materials. BDF-thiophene copolymers are characterized in terms of optoelectronic and thermoelectric properties. The electrical conductivity of chemically doped polymers is found to scale with molar mass, reaching ∼1 S/cm for the highest molar mass and longest backbone-branching point distance.

Titanium-Catalyzed Polymerization of a Lewis Base-Stabilized Phosphinoborane.

The reaction of the Lewis base-stabilized phosphinoborane monomer tBuHPBH2NMe3 (2a) with catalytic amounts of bis(η5:η1-adamantylidenepentafulvene)titanium (1) provides a convenient new route to the polyphosphinoborane [tBuPH-BH2]n (3a). This method offers access to high molar mass materials under mild conditions and with short reaction times (20 °C, 1 h in toluene). It represents an unprecedented example of a transition metal-mediated polymerization of a Lewis base-stabilized Group 13/15 compound. Preliminary studies of the substrate scope and a potential mechanism are reported.

Metamaterials of Auxetic Geometry for Seismic Energy Absorption.

The propagation of earthquake energy occurs primarily through elastic waves. If the seismic force input to a structure can be directly reduced from the source, then the structure can be protected from seismic wave energy. Seismic metamaterials, regarded as periodic structures with properties different from conventional materials, use wave propagation characteristics and bandgaps to dissipate seismic wave energy. When the seismic wave is located in the bandgap, the transmission of seismic wave energy is effectively reduced, which protects the structure from the damage caused by seismic disturbance. In practical application, locating seismic frequencies below ten Hz is a challenge for seismic metamaterials. In the commonly used method, high-mass materials are employed to induce the effect of local resonance, which is not economically feasible. In this study, a lightweight design using auxetic geometry is proposed to facilitate the practical feasibility of seismic metamaterials. The benefits of this design are proven by comparing conventional seismic metamaterials with metamaterials of auxetic geometry. Different geometric parameters are defined using auxetic geometry to determine the structure with the best bandgap performance. Finite element simulations are conducted to evaluate the vibration reduction benefits of auxetic seismic metamaterials in time and frequency domains. Additionally, the relationship between the mass and stiffness of the unit structure is derived from the analytical solution of one-dimensional periodic structures, and modal analysis results of auxetic metamaterials are verified. This study provides seismic metamaterials that are lightweight, small in volume, and possess low-frequency bandgaps for practical applications.

Ambient Temperature Carbene-Mediated Depolymerization: Stoichiometric and Catalytic Reactions of N-Heterocyclic- and Cyclic(Alkyl)Amino Carbenes with Poly(N-Methylaminoborane) [MeNH-BH2]n.

The reactions of the N-heterocyclic carbenes (NHCs) IDipp and ItBu and the cyclic(alkyl)amino carbene (CAAC) CAACMe with polyaminoborane [MeNH-BH2]n were investigated. Stoichiometric quantities of each carbene were found to cause rapid and complete depolymerization, with the major B-N-containing product identified as the NHC-aminoborane adduct, IDipp-BH2NMeH (1), cyclic borazane [MeNH-BH2]3, or borazine [MeNBH]3 with IDipp, ItBu, and CAACMe, respectively. With substoichiometric quantities of IDipp and ItBu (down to 10 and 2.5 mol %, respectively), complete loss of high molar mass material was also detected, indicating that the depolymerization is catalytic. The main products of the reaction with substoichiometric IDipp were IDipp-BH2NMeH (1) and [MeNH-BH2]3 and with substoichiometric ItBu, [MeNH-BH2]3, and [MeNBH]3 with product ratios dependent on the quantity of NHC used. Under analogous conditions with CAACMe, high molar mass material persisted alongside the formation of [MeNBH]3. Further reactivity studies with cyclic borazane [MeNH-BH2]3 and MeNH2·BH3 provided insights into depolymerization pathways. IDipp showed no reactivity toward [MeNH-BH2]3, whereas with 3 equiv of ItBu and CAACMe, the dehydrogenation product [MeNBH]3, was formed. With MeNH2·BH3, 2 equiv of carbene were used as the first acts to accept dihydrogen; the major products with IDipp, ItBu, and CAACMe were IDipp-BH2NMeH (1), [MeNBH]3, and (CAACMeH)HB═NMeH (2), respectively. The double E-H (E = B, N) bond activation product (CAACMeH)HB═NMe(HCAACMe) (3) was isolated from the reaction between 3 equiv of CAACMe and MeNH2·BH3. A unified mechanism for donor-mediated depolymerization of [MeHN-BH2]n is proposed.

Electrochemical synthesis and characterization of self-doped aniline 2-sulfonic acid-modified flexible electrode with high areal capacitance and rate capability for supercapacitors

Polypyrrole and aniline 2- sulfonic acid (CFt/PPy/ASA(0.03) composite was synthesized on carbon felt (CFt) under acid conditions. Here, we report investigated in concentration of ASA on the electropolymerization of the PPy, to improve performance of supercapacitor by a facile and effective one-step electropolymerization method. To form a 3D carbon felt, homogeneous and large grains are grown on the surface with the addition of ASA, which provides high active mass and potential redox materials of pseudocapacitive supercapacitor. The flexible electrode shows a high specific areal capacitance 4000 mF.cm−2 at the scan rate of 10 mV.s−1 and excellent rate capability. A symmetric supercapacitor was also assembled with 1 M H2SO4 electrolyte which delivers a maximum energy density of 18.8 Wh.kg−1 at a power density of 312.5 kW.kg−1, and a maximum power density of 1875 kWh.kg−1 can be reached up while delivering a energy density 2.2 Wh.kg−1. The device displays retention of capacitance performance 82.7% even after 2500 cycles in aqueous electrolyte on the PPy-based materials. Therefore, (CFt/PPy/ASA(0.03) electrode has an important role in practical applications of flexible, wearable and portable electronics.

Energy-Efficient Building Design for a Tropical Climate: A Field Study on the Caribbean Island Curaçao

Based on an extensive literature review on passive building designs for tropical climates, seven energy-efficient building design principles for tropical climate areas were deduced. These are: 1. To orientate a building design in such a direction that it protects from excessive solar radiation; 2. To accommodate for indoor natural ventilation; 3. That it makes maximal use of indirect instead of direct natural light; 4, That it reduces the amount of heat transmission through the roof as much as possible by natural ventilation between roof and ceiling and by lowering the roof surface temperature; 5. By preventing the use of high thermal mass materials; 6. By reducing through the exterior walls as much as possible heat transmission by e.g., preventing direct sunlight on the external walls and applying reflective paints on the external walls and; 7. By creating outdoor and transition spaces such as balconies, terraces atriums and corridors. The insights from the literature review were used as input to conduct a field study to evaluate the practice of applying passive building design principles. To this end, for 626 buildings on the Caribbean island Curaçao, it was investigated to what extent the recommended passive design principles for tropical climates were actually applied. Based on the results of the field study, several recommendations are made to improve the practice of applying passive building principles.

Environmental Value for Heritage Conservation and Urban Sustainability: Adaptation in Widely Divergent Climatic Conditions

ABSTRACT Focusing on traditionally-constructed urban housing in diverse climates, this article illustrates passive means historically providing comfortable living conditions while minimising technology dependence. This is especially relevant today with a tendency towards high-energy solutions, climate change extreme weather events, and pandemics. Minimising energy demands and emissions requires an understanding of theenvironmental value of historic housing in addition to their heritage value. This, to support their own conservation and contributing to passive contemporary architecture strategies. The global potential for mainstreaming retrofit measures is then expanded beyond a restricted heritage sector together with up-scaling localised construction methods and practices. This research revisits traditional solutions and behavioural patterns in Yazd (Iran), Røros (Norway), Santiago-de-Compostela (Spain), and Paramaribo (Suriname). In hot extremes (Yazd), high mass materials in concert with carefully arranged openings and windcatchers have provided low-energy housing. Whereas, wood construction, whether in the cold (Røros) or tropical zones (Paramaribo), relies heavily on material quality, architectural features, and layout. Temperate areas (Santiago-de-Compostela), adapted to seasonal variations for centuries, can share their dynamic qualities. The tendency in many climates to introduce closed air conditioning systems is counterbalanced by a better understanding of traditional systems for environmental control, contributing to a natural ventilation renaissance..

New thermoplastic poly(carbonate-urethane)s based on diphenylethane-derivative chain extenders\u2014the effect of chain extender structure on thermal and mechanical properties

In this study, new thermoplastic sulfur-containing poly(carbonate-urethane)s (PCURs) were synthesized via a one-step melt polyaddition from diphenylethane-derivative diols with two or ten methylene groups in the aliphatic chain, i.e., 4,4′-(ethane-1,2-diyl)bis(benzenethioethanol) (diol E) and 4,4′-(ethane-1,2-diyl)bis(benzenethiodecanol) (diol D) as nonconventional chain extenders, 1,1′-methanediylbis(4-isocyanatobenzene) and 20–60 mol% poly(hexane-1,6-diyl carbonate) diol of overline{M}_{rm{n}} = 860 g mol−1 as a soft segment. The PCURs were studied mainly to describe their thermal and mechanical behaviors by means of DSC, TG and TG coupled with FTIR, and Shore hardness and tensile tests. Moreover, their structure and physicochemical and adhesive properties were determined. The results of the study showed that the kind of the chain extender as well as soft-segment content had an impact on the properties of the polymers obtained. They were amorphous or semicrystalline high molar mass materials. The PCURs based on diol D exhibited lower glass transition temperatures in comparison with those based on diol E with shorter aliphatic chain (− 1–24 °C vs. 13–55 °C). Unfortunately, the former polymers revealed somewhat poorer tensile strengths (up to 45.0 MPa vs. 51.8 MPa). Nevertheless, these values were similar to or higher than those obtained for their commercial analogs. The PCURs being diol D derivatives also showed, in general, lower hardness and the modulus of elasticity but higher elongation at break. All the PCURs exhibited a relatively good thermal stability. However, the polymers derived from diol D revealed higher temperatures of 1, 10 and 50% mass losses compared with diol E-based ones (290–298 °C vs. 285–287 °C, 325–336 °C vs. 314–323 °C, 360–381 °C vs. 348–356 °C, respectively). The newly synthesized sulfur-containing PCURs showed better adhesive properties to copper than the analogous polymer based on butane-1,4-diol as a chain extender.

Thermal performance and fitness of glacial till for rammed earth construction

The search for sustainability caused a revival of earth construction. Rammed earth (RE) construction is often preferred as compaction and stabilization leads to stronger, more consistent materials. Tills are glacial sediments. Historically, they were used for construction and brick making. However, their heterogeneous nature has prevented standardisation into mainstream construction. This work contributes to make earth a reliable building material. It evaluates the suitability of till for RE construction by measuring its geotechnical parameters and comparing them against recommended RE values. The results are consistent with other tills and indicate fitness for RE construction. The tills were successfully stabilized with 5% lime, reaching compressive strengths c.1.09 MPa.Thermal performance is vital in construction. High thermal mass materials such as RE can lower today's unsustainable energy demand for heating and cooling. This work experimentally measures the thermal properties of the till and compares them to other constructions. The experimental values are feed into models to compare thermal performance against other REs and concretes. The rammed till has high conductivity (1.65 W/m K) and specific heat capacity (1218.66 J/kg K) indicating a substantial scope to store heat and poor insulation ability. The thermal diffusivity (7.42 × 10–7 m2/s) suggests that the till will impede heat flow to a greater extent than concrete.In the simulations, the RE assemblies showed the thermal lag typical of high thermal mass materials reducing the fluctuations of external temperature and increasing the internal thermal stability when compared with concrete. All insulated assemblies maintained thermal comfort indexes however, the RE assemblies performed slightly better than concrete; in particular the internally insulated RE, with longer times in superior comfort indices and the smallest temperature drops. The annual heat load of insulated RE is 2–4.2% lower than the concrete construction.

Ring-Opening Polymerisation of Low-Strain Nickelocenophanes: Synthesis and Magnetic Properties of Polynickelocenes with Carbon and Silicon Main Chain Spacers.

Polymetallocenes based on ferrocene, and to a lesser extent cobaltocene, have been well-studied, whereas analogous systems based on nickelocene are virtually unexplored. It has been previously shown that poly(nickelocenylpropylene) [Ni(η5 -C5 H4 )2 (CH2 )3 ]n is formed as a mixture of cyclic (6x ) and linear (7) components by the reversible ring-opening polymerisation (ROP) of tricarba[3]nickelocenophane [Ni(η5 -C5 H4 )2 (CH2 )3 ] (5). Herein the generality of this approach to main-chain polynickelocenes is demonstrated and the ROP of tetracarba[4]nickelocenophane [Ni(η5 -C5 H4 )2 (CH2 )4 ] (8), and disila[2]nickelocenophane [Ni(η5 -C5 H4 )2 (SiMe2 )2 ] (12) is described, to yield predominantly insoluble homopolymers poly(nickelocenylbutylene) [Ni(η5 -C5 H4 )2 (CH2 )4 ]n (13) and poly(tetramethyldisilylnickelocene) [Ni(η5 -C5 H4 )2 (SiMe2 )2 ]n (14), respectively. The ROP of 8 and 12 was also found to be reversible at elevated temperature. To access soluble high molar mass materials, copolymerisations of 5, 8, and 12 were performed. Superconducting quantum interference device (SQUID) magnetometry measurements of 13 and 14 indicated that these homopolymers behave as simple paramagnets at temperatures greater than 50 K, with significant antiferromagnetic coupling that is notably larger in carbon-bridged 6x /7 and 13 compared to the disilyl-bridged 14. However, the behaviour of these polynickelocenes deviates substantially from the Curie-Weiss law at low temperatures due to considerable zero-field splitting.

A strategy for absolute quantitation of isomers using high performance liquid chromatography-ion mobility mass spectrometry and material balance principle

Accurate characterization of isomers is a quite challenge and time-consuming work. A major bottleneck is the lack of relevant reference standards. In this work, we conducted a proof-of-concept study to develop a standard-free method for absolute quantitation of isomers by using high performance liquid chromatography-ion mobility mass spectrometry and material balance principle. The isomer structures were characterized by matching the rank order of experimental collision cross sections (CCSs) to that of theoretical CCSs. Then a time-dependent hydrolysis protocol derived from material balance equation was used for the calculation of the relative correction factor (F). Finally, the multi-level normalized matrix approach was developed to absolutely and precisely quantitate isomeric compounds. To assess this method, quercetin-liver microsome reaction pool was applied. With the developed method, four isomeric metabolites of quercetin were accurately analyzed, and metabolic profiling of quercetin isomeric metabolites was firstly reported with the absolute quantitation results. This is an accurate yet simple method for the absolute quantitation of positional isomers of interest.

The peroxyl radical-induced oxidation of Escherichia coli FtsZ and its single tryptophan mutant (Y222W) modifies specific side-chains, generates protein cross-links and affects biological function

FtsZ (filamenting temperature-sensitive mutant Z) is a key protein in bacteria cell division. The wild-type Escherichia coli FtsZ sequence (FtsZwt) contains three tyrosine (Tyr, Y) and sixteen methionine (Met, M) residues. The Tyr at position 222 is a key residue for FtsZ polymerization. Mutation of this residue to tryptophan (Trp, W; mutant Y222W) inhibits GTPase activity resulting in an extended time in the polymerized state compared to FtsZwt. Protein oxidation has been highlighted as a determinant process for bacteria resistance and consequently oxidation of FtsZwt and the Y222W mutant, by peroxyl radicals (ROO•) generated from AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride) was studied. The non-oxidized proteins showed differences in their polymerization behavior, with this favored by the presence of Trp at position 222. AAPH-treatment of the proteins inhibited polymerization. Protein integrity studies using SDS-PAGE revealed the presence of both monomers and oligomers (dimers, trimers and high mass material) on oxidation. Western blotting indicated the presence of significant levels of protein carbonyls. Amino acid analysis showed that Tyr, Trp (in the Y222W mutant), and Met were consumed by ROO•. Quantification of the number of moles of amino acid consumed per mole of ROO• shows that most of the initial oxidant can be accounted for at low radical fluxes, with Met being a major target. Western blotting provided evidence for di-tyrosine cross-links in the dimeric and trimeric proteins, confirming that oxidation of Tyr residues, at positions 339 and/or 371, are critical to ROO•-mediated crosslinking of both the FtsZwt and Y222W mutant protein. These findings are in agreement with di-tyrosine, N-formyl kynurenine, and kynurenine quantification assessed by UPLC, and with LC-MS data obtained for AAPH-treated protein samples.

Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin

VanA-type resistance to glycopeptide antibiotics in clinical enterococci is regulated by the VanSARA two-component signal transduction system. The nature of the molecular ligand that is recognised by the VanSA sensory component has not hitherto been identified. Here we employ purified, intact and active VanSA membrane protein (henceforth referred to as VanS) in analytical ultracentrifugation experiments to study VanS oligomeric state and conformation in the absence and presence of vancomycin. A combination of sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge (SEDFIT, SEDFIT-MSTAR and MULTISIG analysis) showed that VanS in the absence of the ligand is almost entirely monomeric (molar mass M = 45.7 kDa) in dilute aqueous solution with a trace amount of high molar mass material (M ~ 200 kDa). The sedimentation coefficient s suggests the monomer adopts an extended conformation in aqueous solution with an equivalent aspect ratio of ~(12 ± 2). In the presence of vancomycin over a 33% increase in the sedimentation coefficient is observed with the appearance of additional higher s components, demonstrating an interaction, an observation consistent with our circular dichroism measurements. The two possible causes of this increase in s – either a ligand induced dimerization and/or compaction of the monomer are considered.

New thermoplastic polyurethane elastomers based on aliphatic diisocyanate

New segmented polyurethanes (SPURs) were synthesized by one-step melt polyaddition from a poly(oxytetramethylene)diol of overline{M}_{text n} = 1000 g mol−1 (PTMO) or a poly(hexamethylene carbonate)diol of overline{M}_{text n} = 860 g mol−1 (PHCD) as soft segments, 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane (IPDI), and 2,2′-methylenebis[(4,1-phenylene)methylenesulfanediyl]diethanol (diol E) as an unconventional chain extender. Furthermore, some of SPURs were modified by the addition of a carboxylic group by means of 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid. The effects of the kind and amount of the polymer diol and chain extender used on the structure and properties of the polymers were studied. The polymers were examined by attenuated total reflection Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis (TG), TG–FTIR, differential scanning calorimetry (DSC), Shore A/D hardness and tensile testing. The obtained SPURs were amorphous, colourless, high molar mass materials which showed elastomeric or plastic properties. Their Tgs were in the range of −51 to 29 °C. It was observed that the polymers with a PHCD demonstrated a better segmental miscibility (higher Tgs), as well as greater hardness and tensile strengths, but smaller elongations at break than PTMO-based ones. All of the polymers exhibited a relatively good thermal stability.

Aliphatic polycarbonate-based thermoplastic polyurethane elastomers containing diphenyl sulfide units

New thermoplastic polyurethane elastomers (TPUs) were obtained by a one-step melt polyaddition from 30, 45 and 60 mol% aliphatic polycarbonate diol of M n = 2000 g mol−1 (Desmophen® C2200, Bayer), 1,1′-methanediylbis(4-isocyanatocyclohexane) (HMDI) or 1,6-diisocyanatohexane (HDI) and 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol (acting as a chain extender). The TPUs were examined by FTIR, UV–Vis, atomic force microscopy, X-ray diffraction analysis, differential scanning calorimetry, thermogravimetry (TG) and TG–FTIR. Moreover, their Shore A/D hardness, tensile, adhesive and optical properties were determined. The obtained TPUs were transparent or opaque high molar mass materials, showing amorphous or partially crystalline structures. The HDI-based TPUs exhibited lower glass-transition temperatures than those based on HMDI (from −35 to −31 °C vs. from −20 to 1 °C) as well as a higher degree of microphase separation. The TPUs were stable up to 262–272 °C, taking into account the temperature of 1 % mass loss, with somewhat higher values shown by those from HDI. They decomposed in two stages. The main volatile products of the hard-segment decomposition were carbon dioxide, water and carbonyl sulfide, while aliphatic ethers, aldehydes and unsaturated alcohols, as well as carbon dioxide, originated from the soft-segment decomposition. The synthesized TPUs, with hardness in the range of 80–90°Sh A, possessed a good tensile strength (33.0–38.7 MPa), similar to that of the commercial biodurable medical grade TPU ChronoFlex® AL 80A (37.9 MPa), prepared from aliphatic polycarbonate diol, HMDI and butane-1,4-diol.

Metal-Free Addition/Head-to-Tail Polymerization of Transient Phosphinoboranes, RPH-BH2: A Route to Poly(alkylphosphinoboranes).

Mild thermolysis of Lewis base stabilized phosphinoborane monomers R1R2P–BH2⋅NMe3 (R1,R2=H, Ph, or tBu/H) at room temperature to 100 °C provides a convenient new route to oligo- and polyphosphinoboranes [R1R2P-BH2]n. The polymerization appears to proceed via the addition/head-to-tail polymerization of short-lived free phosphinoborane monomers, R1R2P-BH2. This method offers access to high molar mass materials, as exemplified by poly(tert-butylphosphinoborane), that are currently inaccessible using other routes (e.g. catalytic dehydrocoupling).

Cost Benefit Energy Analysis of the Building Envelope Systems with Ener-Habitat

During the last decade, housing construction in Mexico has increased dramatically, despite the economic and financial crises, it is one of the main drivers of the Mexican economy; the government has supported programs to develop social housing in order to assist low-income families. This type of initiatives has allowed low-income people to own a place to live, but it has also promoted the spread of housing developments with house models of similar characteristics in the very diverse geographical and climatic zones of Mexico. Even though some of the dwellings have few differences depending on the region they belong to, they do not reflect climatic adaptations. The correct selection of the envelope materials is one of the first and most effective passive strategy that must be considered in the design of a housing. However, just selecting the materials by knowing their thermal properties is not enough to make an appropriate decision about the construction system. For this reason, we need a tool like Ener-Habitat, which allows a quick assessment of thermal and energy performance of a building system consisting of several layers, through the time-dependent calculation of heat transfer, suitable for high thermal mass materials, such as those generally used in Mexico and the climates of Mexico with high solar radiation and large temperature swing during the day. The study propose a method to analyze the cost and energy benefit of building systems, and as example analyzes some walls building systems, in a hot-dry climate city of Mexico, during the air conditioning season. This tool allows, at early stages of architectural design, quick assessments for decision taking on the building systems choice, in relation with better energy performance. Ener-Habitat was created by researchers from six academic institutions in Mexico and was funded by the National Council for Science and Technology and the Ministry of Energy of Mexico.

The Effect of Atomic Mass on the Physical Spatial Resolution in EBSD

In this study, bicrystals of silver (Ag) and aluminum (Al) were used to investigate the physical spatial resolution of the electron backscatter diffraction system combining a digital image correlation method. Furthermore, the effect of the accelerating voltage and probe current was investigated on the physical spatial resolution of the lateral and longitudinal resolutions for Ag and Al, respectively. The lateral and longitudinal resolutions show high dependency on the accelerating voltage for a low atomic mass material of Al, In addition, these are almost independent of the accelerating voltage for a high atomic mass material of Ag. Moreover, the probe current does not play any role on both the lateral and longitudinal resolutions. The best lateral resolutions for Al and Ag are 40.5 and 12.1 nm at 10 kV and 1 nA, respectively. The best longitudinal resolutions of 23.2 and 80 nm were obtained at 10 kV and 1 nA for Al and Ag, respectively.

π‐Conjugated Donor and Donor–Acceptor Metallo‐Polymers

Two zinc(II)- and two ruthenium(II) containing π-conjugated metallo-polymers were synthesized and characterized in detail. We could prove by SEC, analytical ultracentrifugation (AUC) and viscosimetry the ruthenium(II) metallo-polymers to be high molar mass materials (M(fs) = 20 000 g · mol(-1) Ru1-2; M(fs) = 34 000 g · mol(-1) Ru1) exhibiting intrinsic viscosities of up to [η] = 192 · cm(3) · g(-1) . Applying spin-coating we produced homogeneous films of the polymers and could, subsequently, investigate the photophysical properties in the solid state. Introducing the Ru(II) metallo-polymers mixed with PCBM[60] as photoactive layer in bulk-heterojunction solar cells resulted in very low efficiencies due to morphology problems.

Estimating molecular masses of petroleum-derived fractions: High mass (>2000 u) materials in maltenes and asphaltenes from Maya crude oil

Molecular mass ranges and average masses of fractions from a heavy Mexican crude oil (Maya) have been studied, using mainly size exclusion chromatography (SEC) and laser desorption-mass spectrometry (LD-MS). Method development focused on the use of planar chromatography and size exclusion chromatography (SEC), to isolate narrow bands of material from solubility-separated fractions of the crude oil. The procedure provides a planar chromatography based method for studying mass ranges in complex hydrocarbon mixtures. It allows the calculation of ‘best estimate’ values for number and mass-averages. These can then be used in average structural parameter (ASP) calculations, for studying structural features of the samples. The method is applicable to both coal and petroleum-derived samples. The molecular mass estimates arrived at in this work for petroleum-derived samples are considerably higher than those reported by other workers for similar samples. The results presented here provide strong evidence for the presence of ions approaching m/ z 10,000 in the Maya asphaltene. The maltene fraction was found to contain a small amount of ions with mass ( m/ z) in excess of 2000.