In this study, the effects of the contents of the soft and hard segments as well as the type of hard segments (linear aliphatic and DABCO) on the properties of PTMO-based segmented ionenes were ...investigated. DSC revealed that soft segment weight fractions up to 75 wt% induced heterogeneous crystallization while the melting temperature decreased due to the lower degree of crystallization. DMA showed the formation of a higher degree of ionic aggregates in both linear aliphatic and DABCO-based PTMO ionenes with 25 wt% of soft segment resulting from strong Coulombic interactions between hard segments. DABCO-based ionenes showed a higher degree of phase separation compared to linear aliphatic analogs and displayed a long-range ordered lamellar structure. In contrast, linear aliphatic ionenes showed the formation of random ionic domains, which was confirmed by SAXS and AFM. TGA showed that the PTMO-based ionenes were thermally stable up to 250 °C and suggested that the DABCO hard segment has a weaker protective effect against the degradation of the PTMO soft segment at elevated temperatures compared to the linear aliphatic hard segment. Uniaxial tensile tests exhibited stress-induced crystallization of PTMO-based ionenes, high elongation at break with linear aliphatic hard segment compared to the DABCO hard segment, and the opposite trend of Young's modulus and ultimate tensile strength by changing the type of the hard segment.
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•PTMO-based segmented ionenes with linear or cyclic hard segments were prepared.•Melting temperature decreased with increasing soft segment content up to 75 wt%.•PTMO-based ionenes were microphase separated regardless of hard segment type.•Linear hard segments produced spherical ionic aggregates.•DABCO-based ionenes exhibited an ordered lamellar structure.
A series of poly(ethylene glycol) (PEG)-based segmented block copolymers were synthesized with two structurally different hard segments, linear and heterocyclic aliphatic amines. Ionenes were ...synthesized via a modified Menshutkin reaction with three different weight fractions of hard domains (amine rich segment) and soft domains (PEG oligomers). TGA results show that both aliphatic and DABCO-based ionenes were thermally stable up to 250 °C. DSC and XRD data indicate that increasing the weight fraction of the soft segment from 25 wt% to 50 wt% triggered better chain packing of the PEG soft segment for both hard segments. Also, the DABCO-based ionenes displayed the highest PEG crystallite purity at 50 wt% of soft segment. The segmented ionenes exhibited high strain elongation percentages at elevated temperatures (i.e., above the PEG melting temperature). The mechanical properties of ionenes changed by varying the nature and the weight fractions of soft and hard domains. DMA analysis concluded that DABCO-based ionenes possess superior elastomeric behavior by having a wider rubbery plateau and higher rubbery plateau storage modulus compared to aliphatic analogs at all weight fractions potentially due to better microphase separation and ionic aggregation. DMA and AFM confirmed that the 25 wt% soft segment ionenes had a relatively higher degree of microphase separation among the other weight fractions.
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•PEG-based segmented ionenes, with two structurally different hard segments, are synthesized.•The degree of crystallinity and phase separation is adjusted with the content of the hard segment.•DABCO-based ionenes show better elastomeric behavior compared to aliphatic analogs.
Electroactive ionenes combining caged‐shaped diazabicyclic cations and aromatic diimides were developed as interlayers in organic solar cells (OSCs). These ionenes reduce the work‐function of ...air‐stable metal electrodes (e.g., Ag, Cu and Au) by generating strong interfacial dipoles, and their optoelectronic and morphological characters can be modulated by aromatic diimides, leading to high conductivity and good compatibility with active layers. The optimal ionene exhibits superior charge‐transport, desirable crystallinity, and weak visible‐absorption, boosting the efficiency of benchmark PM6 : Y6‐based OSCs up to 17.44 %. The corresponding normal devices show excellent stability at maximum power point test under one sun illumination for 1000 h. Replacing Y6 with L8‐BO promotes the efficiency to 18.43 %, one of the highest in binary OSCs. Notably, high efficiencies >16 % are maintained as the interlayer thickness increasing to 105 nm, the best result with interlayer‐thickness over 100 nm.
Diazabicyclic electroactive ionenes with high density of interfacial dipoles are developed as interlayers in organic solar cells. Devices containing the optimal electroactive ionene interlayer give efficiency up to 18.43 % and excellent operational stability with exceptional interlayer thickness tolerance over 100 nm.
Thermally rearranged (TR) polymers and ionic polymers are two material classes which have been employed in leading gas separation membranes. This work introduces a novel approach of combining the ...benzoxazole functionality associated with TR polymers with tailorable cationic groups, yielding a new type of imidazolium-mediated poly(benzoxazole) ionene polymer, “Im-PBO-Ionene” with the aim of enhanced CO2 separation performance. The structural changes exhibited from the Coulombic interactions between the ionene backbone and the “free” ionic liquid (IL) resulted in enhanced gas separation performance, shown in fundamental characterizations, observed through increased diffusivities and more notably, retained high selectivities and 3x or 5x respective increases in CO2 permeability upon the addition of 1 or 2 equivalents of IL per polymer repeat unit. These new high-performance ionenes demonstrate the versatility of ionene design and potential of the ionene + IL material platform for gas separation membranes with versatile incorporation of sophisticated functional and structural features.
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•This cationic ionene incorporates benzoxazole units without thermal rearrangement.•The addition of “free” imidazolium IL into the ionene increases CO2 permeability.•Poly(benzoxazole) imidazolium ionene-IL composites exhibit excellent selectivity.•The rigid ionene backbone + IL balance improves transport behaviors/membrane flexibility.
Thiol-ene photopolymerization was used to generate a series of covalently crosslinked, imidazolium-containing ionene networks. A variety of counteranions were chosen so as to investigate the ...influence of size and basicity on the thermal, mechanical and conductive properties of the resulting networks. Anhydrous conductivities at 20 °C were found to be on the order of 10−6 to 10−10 S/cm and correlated to some degree with Tg; however, Tg-normalization of the curves indicated that this relationship between polymer structure and conductivity was more complex. VFT fitting, along with free ion concentration and ion mobility data, were investigated in order to provide additional insight. Also of interest in this study was the influence of humidity on ionic conductivity. Hydrophilic networks with anions such as Cl, NO3 or OMs were found to exhibit 3- to 5-orders of magnitude enhancement in ionic conductivity (up to 10−3 S/cm) when the relative humidity was increased to 70% while the more hydrophobic networks (PF6 and NTf2) were not influenced. Further experimentation (water uptake, DSC) indicated that the observed enhancements in conductivity were likely due to a combination of plasticization and water-assisted ion transport.
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•Covalently crosslinked ionene networks were prepared by thiol-ene photopolymerization.•A variety of counteranions (hydrophilic vs. hydrophobic networks) were produced.•Conductivities were found to be on the order of 10−6 to 10−10 S/cm.•Humidity greatly impacted the conductivity of the more hydrophilic networks.
The segmented poly(butylene succinate) urethane ionenes (PBSUI) containing secondary amine cation were synthesized by chain extension reaction of dihydroxyl terminated poly(butylene succinate) and ...diethanolamine hydrochloride (DEAH) in the presence of hexamethylene diisocyanate. NMR, DSC, WAXD, POM, SAXS, DMA, and rotational rheometer were used to characterize the structure and properties of the PBSUI, and the tensile properties and hydrolytic degradation of the PBSUI were also investigated. All the results suggest that the content of urethane ionic group plays an important role in tuning the properties of the PBSUIs. The crystallization rate increased first and then decreased and the equilibrium melting temperature increased gradually with increasing urethane ionic group content. The maximum crystallization rate was obtained for PBSUI with 3 wt% DEAH. The obvious clusters formed by aggregation of urethane ionic group were evidenced by DMA and SAXS for the PBSUI containing 5 wt% DEAH. The complex viscosity increased significantly with increasing urethane ionic group content due to the physical crosslinking effect resulted from aggregation of ionic groups. The storage modulus increased with DEAH content increased up to 3 wt %, while decreased with further increasing DEAH content. Tensile testing indicated incorporation of urethane ionic group did not change the tensile properties apparently. The hydrolytic degradation rate of the samples increased with the increase in urethane ionic group content which was mainly ascribed to the increased hydrophilicity.
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A series of polymer based on spirocyclic quaternary ammonium (QA) cations having 5-/6- and 6-/6- membered rings were designed and prepared from tetrakis(bromomethyl) monomers to investigate the ...alkaline and fuel cell stability of spirocyclic ionenes. The alkaline stability testing of model compounds and DFT calculations showed that the spirocyclic QA having 5-/6-membered rings based on phenyl and biphenyl showed a better stability than that of the spirocyclic QA with naphthalene 6-/6-membered rings probably due to the strong electro-withdrawing effect of naphthalene rings. Although the high molecular weight polymer with naphthalene rings could not be obtained, the spirocyclic ionenes based on phenyl or biphenyl showed high molecular weight. Thus, the blending membrane with rigid NPBI have been fabricated to mitigate the water solubility of spirocyclic ionenes due to their high IEC values. The blending membrane showed a high ionic conductivity even at elevated temperature without any excessive swelling in spite of its high IEC value. Employing the spirocyclic ionenes as membrane, the H2/O2 single cell at 60 °C was firstly demonstrated. A peak power density of 135 mW cm−2 was achieved for PP80N20 membrane. Surprisingly, the fuel cell device durability provided a counterintuitive data that showed that spirocyclic ionenes with excellent alkaline stability were not superior in device function assessment. A rapid ring-opening degradation as confirmed by NMR technique for the spirocyclic ionenes was observed in device testing. These results that stability investigation gives us new directions for polymer and cations designs for highly durable devices.
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•A series of spirocyclic quaternary ammonium (QA) cations were designed and synthesized.•The results indicated that the spirocyclic QA having 5-/6-membered rings based on phenyl have a best alkaline stability.•A maximum power density of 135 mW cm−2 was achieved for PP80N20 membrane.
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•DABCO-containing isomeric polymers form hydrogels.•The topology of the polymer is controlled by the disubstitution pattern of an aromatic core.•The ortho-isomer showed very superior ...shape persistent, self-standing and self-healing properties compared to its meta- and para-analogues.•The healing process occurred without involving oppositely charged species.
DABCO-containing polymers based on a disubstituted phenylene dibenzamide core constitute versatile gelators enabling the formation of hydrogels for different applications. In this work we have found that the polymer topology, controlled by the disubstitution pattern of the aromatic core, plays a crucial role on the self-healing properties of the corresponding hydrogels. Specifically, the ortho-isomer showed very superior shape persistent, self-standing and self-healing properties compared to its meta- and para-analogues. Interestingly, the healing process occurred without the need of involving oppositely charged species.
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•Chitosan/ionene/carboxymethylcellulose PECs with high self-antibacterial activity.•High sorption efficiency of ionene containing PEC sponges in multi-pollutant ...systems.•Pseudo-first-order kinetic model fits the best the kinetic data.•Preferential sorption of Cr2O72− and Pb2+ ions in multi-component systems.•Composite tricomponent PEC sponges with high recyclability.
Tricomponent polyelectrolyte complex (PEC) composite cryogels, with remarkable sorption capacity of multiple contaminants and self-antibacterial properties were fabricated from chitosan (CS) and aromatic ionene type polycations evenly dispersed in carboxymethyl cellulose (CMC) aqueous solution. Fast cryostructuration at −196 °C (5 min) and overnight at −18 °C conducted to pre-PECs which, after exposure to a source of H+ and freeze-drying, led to PEC composite sponges. The PECs were characterized by FTIR, SEM, EDX, streaming potential titrations, swelling kinetics, swelling at equilibrium as a function of pH, and compressive tests. These PECs were able to simultaneous adsorb oxyanions (HCrO4−, H2PO4−, HAsO42−), and heavy metal ions (HMIs) (Cu2+, Cd2+, Pb2+), and to kill ∼100 % of Gram+ (Staphylococcus aureus) bacteria. Only the tricomponent PECs were able to kill 100 % of Gram- (Escherichia coli) bacteria, while the bicomponent PECs (containing only CS and CMC) were less efficient in this case (only 70 % inhibition of bacteria). The pseudo-first-order kinetic model fitted the best the kinetic data, suggesting the sorption of pollutants by physisorption. In multicomponent systems, HCrO4− ions are preferred, the selectivity coefficients being higher in the case of tricomponent PECs than in the case of bicomponent PECs, while in the case HMIs, Pb2+ ions were preferentially selected. The sustainability of the PEC composite cryogels was demonstrated by their reuse up to five sorption/desorption cycles, with a decrease of the sorption capacity in the fifth cycle of 7 % for H2PO4−, 8.1 % for HCrO4−, and 6.9 % for HAsO42− when tricomponent PEC cryobeads were used as sorbents. All these abilities recommend the PEC composite cryogels as potential materials for filters suitable for point-of-use water purification.
Segmented imidazolium ionenes with poly (tetramethylene oxide) (PTMO) soft segments and ionic, bis-imidazolium hard segments formed nonwoven fibrous mats upon electrospinning. The segmented ...imidazolium ionenes exhibited high thermal stability, excellent mechanical properties, and two glass transition temperatures indicative of microphase separation. Tensile analysis revealed strain-induced crystallization for ionenes with a 2 kg/mol PTMO soft segment and increased stress at break with increasing soft segment molecular weight. Solution rheology enabled the determination of solvent quality, overlap and entanglement concentrations, and the influence of ion content on solution properties. Fiber diameters for polymeric fibers electrospun from acetonitrile suggested solution polyelectrolyte behavior that was independent of the PTMO molecular weight. This work reports the successful electrospinning of segmented imidazolium-containing ionenes and an in-depth analysis of their thermomechanical and solution properties.
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•Tensile testing indicated that strain-induced crystallization occurred when the PTMO molecular was above 1 kg/mol.•Variations in solvent polarity changed the solution conformation and degree of counterion condensation.•Changing charge density in a singular solvent revealed an upper limit for charge dissociation at approximately 20 wt%.•The imidazolium ionenes formed electrospun fibrous mats with characteristics similar to other polyelectrolytes.
