Ionic Chain Research Articles

Conjugated ionic porphyrins as the cathode interlayer materials in organic solar cells

Abstract Cathode interlayer materials (CIMs) play very important roles in organic solar cells (OSCs). In this study, we synthesize three porphyrin CIMs Br−FNEZnP-OE, Br−FNEZnP-TC16 and SO3−FNEZnP-TC16 with the same conjugated backbones but different ionic side chains at the fluorene units and different substituents at the porphyrin cores. Because Br−FNEZnP-TC16 and SO3−FNEZnP-TC16 are substituted with hydrophobic alkyl-thienyls while Br−FNEZnP-OE contains more hydrophilic di-ethanediol ester phenyls at the porphyrin cores, Br−FNEZnP-TC16 and SO3−FNEZnP-TC16 are soluble in methanol but insoluble in water while Br−FNEZnP-OE soluble in not only methanol but also water. The bulk heterojunction (BHJ) OSCs based on PTB7:PC71BM (PTB7: poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-di-yl] [3-fluoro-2-[(2-ethylhexy)carbonyl]thienyl[3,4-b]thiophenediyl]], PC71BM: [6,6]-phenyl C71butyric acid methyl ester) with Br−FNEZnP-TC16 and SO3−FNEZnP-TC16 cathode interlayers (CILs) exhibit high power conversion efficiencies (PCEs) of 9.07% and 8.86%, which are enhanced by 66.4% and 62.6%, respectively, with simultaneously improved open circuit voltages, short circuit currents (Jsc) and fill factors compared with those of the devices without any CIL (PCE: 5.45%), and even higher than those of the devices with widely used PFN CILs (PCE: 7.74%) (PFN: poly [(9,9-bis(3´-(N,N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9–dioctylfluorene)). In contrast, the OSCs with Br−FNEZnP-OE CILs only show a slightly enhanced PCE of 6.55% with a reduced Jsc compared with that of the control devices with no CILs. We also investigate why the performance of the devices with Br−FNEZnP-OE CILs is inferior to those with Br−FNEZnP-TC16 and SO3−FNEZnP-TC16 CILs.

Classical Drude Polarizable Force Field Model for Methyl Phosphate and Its Interactions with Mg2.

Phosphate groups are essential components of nucleic acids and proteins, whose interactions with solvent, metal ions, and ionic side chains help control folding and binding. Methyl phosphate (MP) represents a simple analog of phosphate moieties that are post-translation modifications in proteins and present at the termini of nucleic acids, among other environments. In the present study, we optimized parameters for use in polarizable molecular dynamics simulations of MP in its mono- and dianionic forms, MP- ≡ CH3HPO4- and MP2- ≡ CH3PO42-, along with P i2- ≡ HPO42-, in the context of the classical Drude oscillator model. Parameter optimization was done in a manner consistent with the remainder of the Drude molecular mechanics force field, choosing atomic charges and polarizabilities to reproduce molecular properties from quantum mechanics as well as experimental hydration free energies. Optimized parameters were similar to existing dimethyl phosphate parameters, with a few significant differences. The developed parameters were then used to compute magnesium binding affinities in aqueous solution, using alchemical molecular dynamics free energy simulations. Good agreement with experiment was obtained, and outer sphere binding was shown to be predominant for MP- and MP2-.

Monovalent cations permselective membranes with zwitterionic side chains

Monovalent cations permselective membranes (MCPMs) which can selectively transport monovalent and reject the multivalent cations are key materials for waste water treatment, mining of valuable seawater metal ions, acid recovery in hydrometallurgy etc. High flux and good selectivity are desired characteristics for practical applications of MCPMs. In this study, we have synthesized functionalized MCPMs containing zwitterionic side chain comprising two quaternary ammonium groups and one sulfonic acid group. Distinct nano-phase separation between aromatic main chain and the ionic side chains was observed by the atomic force microscopy. The resulting MCPMs showed excellent H+ flux (16.92 mol h−1m−2) in electrodialysis (ED) process. Because the electrostatic repulsive effect of zwitterionic structure, the synthesized MCPM exhibits excellent Na+/Mg2+ selectivity of 7.4 and remarkably good H+/Zn2+ selectivity of 23.5.

Thermal and Mechanical Behavior of New Transparent Thermoplastic Polyurethane Elastomers Derived from Cycloaliphatic Diisocyanate.

New transparent thermoplastic polyurethane elastomers (TPURs) with the hard-segment content of ≈50 mass % were synthesized by one-step melt polyaddition of 1,1′-methanediylbis(4-isocyanatocyclohexane), 2,2′-methylenebis[(4,1-phenylene)-methylenesulfanediyl]diethanol (diol E), 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid (DMPA), a poly(oxytetramethylene) diol of = 1000 g/mol (PTMO), or a poly(hexametylene carbonate) diol of = 860 g/mol (PHCD). Herein, I prepared TPURs in which 20, 40, and 60 mol % of diol E was replaced with DMPA, an ionic chain extender. The structure of polymers was examined by ATR-FTIR. Their thermal and mechanical behaviors were determined by means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile tests, and Shore A/D hardness. Their optical properties are described. Generally, the addition of carboxyl groups to the polymer resulted in decreases in their thermal stability, transparency, and refractive indexes. Furthermore, the use of different soft segments revealed significant differences in both mechanical and thermal properties of the polymers obtained.

Quantum-confined superfluid: From nature to artificial

Biological ion channels show that ultrafast ions and molecules transmission are in a quantum way of single molecular or ionic chain with a certain number of molecules or ions, and we define it as “quantum-confined superfluid” (QSF). This ordered ultrafast flow in the confined channel can be considered as “quantum tunneling fluid effect” with a “tunneling distance”, which is corresponding to the period of QSF. Recent research demonstrated that artificial biomimetic nanochannels also showed the phenomenon of QSF, such as ion and water channels. The introduction of QSF concept in the fields of chemistry and biology may create significant impact. As for chemistry, the QSF effect provides new ideas for accurate synthesis in organic, inorganic, polymer, etc. We believe the implementation of the idea of QSF will promote the development of QSF biochemistry, biophysics, bioinformatics and biomedical science.

Evidence for cis Amide Bonds in Peptoid Nanosheets.

Peptoid nanosheets are supramolecular protein-mimetic materials that form from amphiphilic polypeptoids with aromatic and ionic side chains. Nanosheets have been studied at the nanometer scale, but the molecular structure has been difficult to probe. We report the use of 13C-13C dipolar recoupling solid-state NMR measurements to reveal the configuration of backbone amide bonds selected by 13C isotopic labeling of adjacent α-carbons. Measurements on the same molecules in the amorphous state and in nanosheets revealed that amide bonds in the center of the amino block of peptoid (NaeNpe)7-(NceNpe)7 (B28) favor the trans configuration in the amorphous state and the cis configuration in the nanosheet. This unexpected result contrasts with previous NMR and theoretical studies of short solvated peptoids. Furthermore, examination of the amide bond at the junction of the two charged blocks within B28 revealed a mixture of both cis and trans configurational states, consistent with the previously predicted brickwork-like intermolecular organization.

Impacts of ammonium based ionic liquids alkyl chain on thermodynamic hydrate inhibition for carbon dioxide rich binary gas

In this work, the thermodynamic inhibition impact of four ammonium-based ionic liquids (AILs) on CO2 rich mixed gas hydrate system (70–30mol% CO2+CH4) is experimentally studied, and the observed behaviour is modelled. The studied AILs are; tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPrAOH) and tetrabutylammonium hydroxide (TBAOH). Initially, the impact of 10wt% AILs in an aqueous solution on the CO2 enriched binary gas phase boundary is evaluated by measuring the dissociation temperature in the pressure range of 1.90–5.10MPa. The thermodynamic inhibition influence of AILs is quantitatively analyzed by calculating the hydrate suppression temperatures for all studied systems. Further, the Clausius–Clapeyron equation is used to determine the molar hydrate enthalpy of dissociation (∆Hdiss) for the studied systems. The results revealed that the inhibition influence of AILs is observed to be decreasing with the increasing alkyl chain length of AILs. Excluding TBAOH, all the other studied AILs act as thermodynamic inhibitors due to the relatively shorter alkyl chain. The ∆Hdiss results of the binary mixed gas system in the presence and absence of AILs revealed that the presence of TMAOH, TEAOH and TPrAOH has negligible effect in hydrate cages formation. However, TBAOH exhibited a significant change in ∆Hdiss which indicates the semi-clathratic nature of it. Among the considered AILs, TMAOH shown better thermodynamic impact attributed to its shortest alkyl chain length. Therefore it is further investigated for various concentrations (1, 5 and10wt%). Moreover, the measured, mixed gas hydrate phase boundaries of various aqueous AILs solutions are also predicted via electrolyte model proposed by Dickens and Quinby-Hunt and are found to be in good agreement with the experimental data apart from TBAOH. Therefore, this study is relevant for the understanding of structural variations (alkyl chain elongation) of AILs on the hydrate phase stability of the high CO2 content mixed gas system.

Evaluation of ionic liquids supported on silica as a sorbent for fully automated online solid-phase extraction with LC-MS determination of sulfonamides in bovine milk samples.

Sulfonamides are antibiotics widely used in the treatment of diseases in dairy cattle. However, their indiscriminate use for disease control may lead to their presence in tissues and milk and their determination requires a sample preparation step as part of an analytical approach. Among the several sample preparation techniques available, those based upon the use of sorptive materials have been widely employed. Recently, the application of ionic liquids immobilized on silica surfaces or polymeric materials has been evaluated for such an application. This manuscript addresses the evaluation of silica-based ionic liquid obtained by a sol-gel synthesis process by basic catalysis as sorbent for online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry for sulfonamides determination. Infrared vibrational spectroscopy confirmed the presence of the ionic liquid on the silica surface, suggesting that the ionic liquid was anchored on to the silica surface. Other sorbents varying the ionic liquid alkyl chain were also synthesized and evaluated by off-line solid-phase extraction in the sulfonamide extraction. As the length of the alkyl chain increased, the amount of extracted sulfonamides decreased, possibly due to a decrease in the electrostatic interaction caused by the reduction in the polarity, as well as the presence of a hexafluorophosphate anion that increases the hydrophobic character of the material. The use of 1-butyl-3-methylimidazolium hexafluorophosphate as a selective ionic liquid sorbent enabled the isolation and sulfonamide preconcentration in bovine milk by online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry. The limit of quantification for the method developed was 5-7, 5 μg/mL, with extraction recoveries ranging between 74 and 93% and intra- and interassay between 1.5-12.5 and 2.3-13.1, respectively.

Castor oil-based cationic waterborne polyurethane dispersions: Storage stability, thermo-physical properties and antibacterial properties

In this study, castor oil and its derivative were used to prepare cationic waterborne polyurethane dispersion using N-methyl diethanolamine (MDEA) as ion center. The effect of polyol functionalities and the ionic chain extender contents on the particle size and antibacterial properties of the polyurethane dispersions, and thermo-mechanical, thermal stability, mechanical properties, water/solvent uptakes of the resulting polyurethane films were thoroughly investigated. Moreover, all the polyurethane dispersions exhibit enhanced antibacterial activity against Vibrio parahaemolyticus with the rise of MDEA content and the reduction of polyol functionalities, but rarely antibacterial activity to Listeria monocytogenes. To the best of my knowledge, this work for the first time extensively investigate the structure-property relationships of castor oil based cationic waterborne polyurethane dispersions and their polyurethane films.

Dual ionic cross-linked double network hydrogel with self-healing, conductive, and force sensitive properties

Conventional chemically cross-linked double network hydrogels (DN hydrogels) are considered as one of the toughest soft materials. However, they lack self-healing properties due to their non-reversible covalent bonds. In this work, we propose a new design strategy to synthesize a dual ionic cross-linked polyethylene glycol (PEG)/poly(acrylamide-co-acrylic acid) (PAMAA) DN hydrogels, consisting of an ionic cross-linked linear chain extension of PEG and a PAMAA-Fe3+ as the first and second physical networks, respectively. Due to the reversible non-covalent bonds in both networks (Fe3+ coordination interactions and hydrogen bonds), the DN hydrogels can achieve high mechanical properties (σf of ∼0.36 MPa and strain of ∼1350%) and complete self-healing ability within 12 h. Moreover, due to the free ions diffusion in the water medium of the DN hydrogels, the as-prepared hydrogels also exhibited electrical conductivity and stretch sensitivity. Our results offer a new design strategy to improve the strength and self-healing ability of DN hydrogels by introducing a dual ionic cross-linking within the network, which we hope will provide an alternative focus for the design of tough and self-healing hydrogels with desirable properties.

Poly(arylene ether nitrile) anion exchange membranes with dense flexible ionic side chain for fuel cells

To resolve the excessive swelling and undesirable alkaline stability of densely functionalized type anion exchange membranes (AEMs) and to obtain high performance AEMs, quaternary ammonium-functionalized poly(arylene ether nitrile) (QPAEN) AEMs with dense flexible ionic side chain are prepared via nucleophilic substitution polycondensation, demethylation reaction and Williamson reaction. The densely pendent flexible long side chains with QA groups at the end provide a high conductivity and the introduced strong polar nitrile groups result in lower water uptake, excellent dimensional stability and strong alkali resistance of the AEMs. The QPAEN membrane with IEC of 1.78meqg−1 exhibits the highest hydroxide conductivity of 116.0 mScm−1 at 80°C. The high conductivity is attributed to the well-developed hydrophilic/hydrophobic phase separated morphology that constructs efficient ion conducting pathways in the membranes. High retention of hydroxide conductivity (80.2%) and ionic exchange capacity (IEC) (86.0%) was observed for the QPAEN-0.4 membrane in the degradation test in a 2M aqueous KOH solution for 480h. Moreover, the single cell performance of the as-prepared AEMs was greatly enhanced and a high peak power density of 251.3mWcm−2 at 60°C was observed.

Stimuli-responsively porating gels by condensation.

A polyurethane (PU) resin derived from glycerol and hexamethylene diisocyanate and an imidazolium bromide ionic liquid chain terminator yield a stimuli-responsive resin that reversibly porates as a solvation response.

Mass-imbalanced ionic Hubbard chain

A repulsive Hubbard model with both spin-asymmetric hopping (${t_\uparrow\neq t_\downarrow}$) and a staggered potential (of strength $\Delta$) is studied in one dimension. The model is a compound of the mass-imbalanced (${t_\uparrow\neq t_\downarrow}$, ${\Delta=0}$) and ionic (${t_\uparrow = t_\downarrow}$, ${\Delta>0}$) Hubbard models, and may be realized by cold atoms in engineered optical lattices. We use mostly mean-field theory to determine the phases and phase transitions in the ground state for a half-filled band (one particle per site). We find that a period-two modulation of the particle (or charge) density and an alternating spin density coexist for arbitrary Hubbard interaction strength, ${U\geqslant 0}$. The amplitude of the charge modulation is largest at ${U=0}$, decreases with increasing $U$ and tends to zero for ${U\rightarrow\infty}$. The amplitude for spin alternation increases with $U$ and tends to saturation for ${U\rightarrow\infty}$. Charge order dominates below a critical value $U_c$, whereas magnetic order dominates above. The mean-field Hamiltonian has two gap parameters, $\Delta_\uparrow$ and $\Delta_\downarrow$, which have to be determined self-consistently. For ${U<U_c}$ both parameters are positive, for ${U>U_c}$ they have different signs, and for ${U=U_c}$ one gap parameter jumps from a positive to a negative value. The weakly first-order phase transition at $U_c$ can be interpreted in terms of an avoided criticality (or metallicity). The system is reluctant to restore a symmetry that has been broken explicitly.

Role of different nanoparticulate cores on the thermal, mechanical and electrochemical cycling behaviour of nanoscale hybrid ionic fluids

Herein, two different nanoscale hybrid ionic fluids (NHIFs) have been demonstrated as potential electrolytes for electrochemical cyclic applications. These NHIFs are prepared by tethering 1-ethyl-3-(3-trimethoxysilylpropyl)-imidazolium bis(trifluoromethanesulfonyl)imide ionic liquids to the surfaces of SiO2 and Al2O3 nanoparticulate cores by simple sol–gel process, resulting in a class of versatile, stable and high-performance gel like materials. Both the NHIFs are mechanically compliant and thermally stable. The NHIFs show wide electrochemical stability window of 8volt that does not shrink with the increase of temperature. Furthermore, the NHIF electrolytic cells containing planar steel electrodes show very good capacitance retentivity (>90%) and long term cyclic stability above room temperature. Relatively higher grafting density of the ionic liquid chains to SiO2 nanoparticles as compared to Al2O3 nanoparticles enables the respective NHIF to show better morphology with superior thermal, mechanical, electrical and electrochemical properties than its Al2O3 tethered analogue. Results obtained from the study highlight the applicability of these hybrid ionic fluids as promising electrolytes in secondary charge storage devices, even at higher temperature.

Influence of Imidazolium Ionic Liquids on the Interactions of Human Hemoglobin with DyCl3, ErCl3, and YbCl3 in Aqueous Citric Acid at T = (298.15, 303.15, and 308.15) K and 0.1 MPa

Density, sound velocity, viscosity, surface tension, and molar conductivity for DyCl3·6H2O, ErCl3·6H2O, and YbCl3·6H2O from (0.002 to 0.012) mol·kg–1 in aqueous solutions of (a) citric acid (0.005 mol·kg–1) (b) citric acid + human hemoglobin (1 g·kg–1) and (c) citric acid + human hemoglobin +1-alkyl-3-methylimidazolium chloride (0.001 mol·kg–1) ([RMIMCl], R = ethyl, butyl, and hexyl) at T = (298.15, 303.15, and 308.15) K and 0.1 MPa are reported. Densities were used to calculate the apparent molar volumes. The viscosity data are analyzed and interpreted using the extended Jones–Dole equation for lanthanide chloride to calculate viscosity A- and B-coefficient values. The varying trends of the aforesaid physicochemical parameters have been interpreted in terms of the solute–solute and solute–solvent interactions. An attempt has been made to investigate the influence of ionic liquid alkyl chain length on the interacting activities of lanthanide chloride with citric acid and the critical role being played by ...

Molecular dynamics simulation of the atomistic monolayer structures of N-acyl amino acid-based surfactants

Atomic molecular dynamics simulations have been performed on the monolayer systems of N-acyl amino acid-based surfactants. The role of intermolecular hydrogen bonds and ionic side chain length of dicarboxylate surfactants were investigated through radial and spatial distribution functions. It was found that the hydrogen bonding capability between surfactants was the major factor determining the surface area each surfactant could occupy. Tighter packing of surfactants would lead to a weaker interaction with water molecule, and the protonation of carboxylate groups resulted in stronger inter-surfactant interactions. The hydrogen bonds with water molecules were found to prevail between the carboxylate groups, and regular cage-like water distributions surrounding the surfactant headgroups were seen. The introduction of divalent ions leads to a significant increase of counterion binding, and their intramolecular and intermolecular bindings of calcium ions were also well characterised. The intramolecular chelation of calcium ions was found impossible between the carboxylate groups for N-acyl glutamate due to its flexible side chain.

Novel Synthetic Approach to Tune the Surface Properties of Polymeric Films: Ionic Exchange Reaction between Sulfonated Polyarylethersulfones and Ionic Liquids

ABSTRACTCurrently, no studies dealing with the role played by ionic liquids on tailoring surface features of polymer films are available. In this work, ionic liquids influence on the surface of sulfonated polyarylethersulfones was investigated. Sulfonated polyarylethersulfones with different degrees of sulfonation were synthesized; their surface properties were modulated through an ionic exchange reaction between the K+ cation of sulfonated polyarylethersulfones and ionic liquids, synthesized changing the length of cation of apolar groups. Hydrophobic properties of sulfonated polyarylethersulfones–ionic liquids films improve with both an increase in degrees of sulfonation and the length of ionic liquids alkyl chains due to higher surface roughness, as shown by scanning electron microscopy and atomic force microscopy.

Optical Properties of Benzotriazole-Based Conjugated Polyelectrolytes

A series of conjugated polyelectrolytes (CPEs) based on an electron-deficient polybenzotriazole backbone with various pendant ionic functionalized side chains were synthesized directly from the corresponding ionic monomers. Of particular interest was to use the different chemical structures to understand how the optical features are influenced by the ionic side chains. We found that interchain aggregation is favored in low dielectric constant solvents for cationic CPEs. Moreover, aggregated species absorb at longer wavelengths and exhibit higher fluorescence quantum yields.

Effects of conformational ordering on protein/polyelectrolyte electrostatic complexation: ionic binding and chain stiffening.

Coupling of electrostatic complexation with conformational transition is rather general in protein/polyelectrolyte interaction and has important implications in many biological processes and practical applications. This work studied the electrostatic complexation between κ-carrageenan (κ-car) and type B gelatin, and analyzed the effects of the conformational ordering of κ-car induced upon cooling in the presence of potassium chloride (KCl) or tetramethylammonium iodide (Me4NI). Experimental results showed that the effects of conformational ordering on protein/polyelectrolyte electrostatic complexation can be decomposed into ionic binding and chain stiffening. At the initial stage of conformational ordering, electrostatic complexation can be either suppressed or enhanced due to the ionic bindings of K+ and I− ions, which significantly alter the charge density of κ-car or occupy the binding sites of gelatin. Beyond a certain stage of conformational ordering, i.e., helix content θ > 0.30, the effect of chain stiffening, accompanied with a rapid increase in helix length ζ, becomes dominant and tends to dissociate the electrostatic complexation. The effect of chain stiffening can be theoretically interpreted in terms of double helix association.

Association of DNA-Stabilized Carbon Nanotubes and Cationic Surfactants: Ionic Strength and Chain Length Effects

Processing carbon nanotubes (CNTs) into functional materials requires usage of multicomponent systems. Additives such as ionic surfactants, complex macromolecules (i.e., DNA, proteins), or colloidal nanoparticles are used for this purpose. Unfortunately, the high intrinsic nonideality of these systems makes predictions and simulations of their behavior challenging. That is why experimental investigations on the overall colloidal behavior are fundamental in developing CNT-based technologies. To that purpose, we have recently started a systematic characterization of (pseudo)ternary systems containing carbon nanotubes. In a previous study, we have characterized the re-entrant behavior of single-stranded DNA (ssDNA)/CNT in the presence of an oppositely charged surfactant. The ratio between ssDNA/nanotubes and surfactant defines the overall associative behavior. Irreversible aggregation is found close to the isoelectric point, while negatively or positively charged surfactant–ssDNA/nanotube complexes appear at...