In this work, hyperbranched polycarbonate‐poly(ethylene oxide) (PEO)‐based solid polymer electrolytes (HBPC‐SEs) are successfully synthesized via a straightforward organo‐catalyzed ...“A1”+“B2”‐ring‐opening polymerization approach. The temperature‐dependent ionic conductivity of HBPC‐SEs, composed of different polycarbonate linkages and various LiTFSI concentrations, is investigated. The results demonstrate that HBPC‐SE with an ether‐carbonate alternating structure exhibits superior ionic conductivity, attributed to the solubility of Li salts in the polymer matrix and the mobility of the polymer segments. The HBPC1‐SE with 30 wt% LiTFSI presents the highest ionic conductivities of 2.15 × 10−5, 1.78 × 10−4, and 6.07 × 10−4 Scm−1 at 30, 60, and 80 °C, respectively. Compared to traditional PEO‐based electrolytes, the incorporation of polycarbonate segments significantly enhances the electrochemical stability window (5 V) and Li+ transference number (0.53) of HBPC‐SEs. Furthermore, the LiFePO4/HBPC1‐SE‐3/Li cell exhibits exceptional rate capability and long‐cycling performance, maintaining a discharge capacity of 130 mAh g−1 at 0.5C with a capacity retention of 95% after 300 cycles.
Hyperbranched polycarbonate‐poly(ethylene oxide)‐based solid polymer electrolytes (HBPC‐SEs) are synthesized. The HBPC1‐SEs exhibit high ionic conductivities, with an electrochemical stability window of 5 V and Li+ transference number of 0.53. The LiFePO4/HBPC1‐SE‐3/Li cell maintains a discharge capacity retention of 95% at 0.5C after 300 cycles.
PEO-PANI/TiNPs nanocomposite films with different concentrations of TiNPs were deposited on the glass substrates using a simple casting method. The structural, thermal, morphological, optical, and ...electrical properties of these nanocomposite films were studied. The amorphous phase becomes dominant when TiNPs are added to the polymer blend, supporting the physical interactions between the polymer chains and TiNPs. The melting enthalpy decreased gradually from 100.6 J/g to 63 J/g by adding 16 wt% of TiNPs in the nanocomposite films; in contrast, the melting temperatures increased. A change in the surface morphology of the PANI/TiNPs nanocomposite films was found, and changes in the optical spectra, band gap energy, refractive index, and electrical conductivity accompanied it. For instance, the sheet resistance (
R
s
) of the PEO-PANI film is 2.31 × 10
8
Ω/sq, and this value decreases continuously to 4.85 × 10
7
Ω/sq with increasing the TiNPs concentration up to 16 wt%. At the same time, the electrical conductivity (
σ
) value of PEO-PANI/TiNPs increases from 4.33 × 10
−5
S/cm to 1.38 × 10
−4
S/cm.
•Ionic liquid cations with oligo(ethylene oxide) side chains have been prepared.•The effect of the side chain length on Li+ solvation was studied.•The effect of the ionic liquids as solid polymer ...electrolyte plasticizers is reported.•The increased solvation of the longer side chains leads to improved performance.
Ternary solid polymer electrolytes (TSPEs) with ionic liquids (ILs) including alkyl-based ammonium cations and low coordinating anions suffer from the lack of Li+ ion coordination by the ILs compared to the immobile polymer backbone, in terms of Li+ ion transport. Thus, solvating ionic liquids (SILs) with an oligo(ethylene oxide) side chain attached onto the cation were prepared to improve the interaction between Li+ and the IL and accelerate Li+ transport in TSPEs. A variety of methods, such as pulsed field gradient nuclear magnetic resonance spectroscopy, Li metal plating/stripping and measurements of Sand's times were used to show that Li+ ion transference numbers increase with the oligo(ethylene oxide) side chain length in SIL-based TSPEs, which results in faster Li+ ion transport and translates into much slower lithium depletion at a given current, thereby delaying the onset of fast dendrite growth of lithium metal.
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Manipulation, focusing, and separation of submicron- and nanoparticles such as extracellular vesicles (EVs), viruses and bacteria have broad applications in disease diagnostics and therapeutics. ...Viscoelastic microfluidic technology emerges as a promising technique, and it shows an unparalleled capacity to manipulate and separate submicron particles in a high resolution based on the elastic effects of non-Newtonian mediums. The maximum particle separation resolution for the reported state-of-the-art viscoelastic microfluidics is around 200 nm. To further enhance the reseparation resolution, this work develops a viscoelastic microfluidic device that can achieve a finer separation resolution up to 100 nm, by optimising the operating conditions such as flow rate, flow rate ratio and polyethylene oxide (PEO) concentration. With these optimised conditions, we separated a ternary mixture of 100 nm, 200 nm and 500 nm polystyrene particles, with purities above 90%, 70% and 82%, respectively. Furthermore, we also applied the developed viscoelastic microfluidic device for the separation of cancer cell-secreted extracellular vesicles (EVs) into three different size groups. After single processing, the separation efficiencies for small EVs (sEVs, <150 nm), medium EVs (mEVs, 150-300 nm), and large EVs (>300 nm) were 86%, 80% and 50%, respectively. The enrichment factors for the three EV groups were 2.4, 1.1 and 1.3, respectively. Moreover, we observed an unexpected effect of high PEO concentrations (2000-5000 ppm) on the lateral migration of nanoparticles where nanoparticles of up to 50 nm surprisingly can migrate and concentrate at the middle of the microchannel. This simple and label-free viscoelastic microfluidic device possesses excellent potential for sorting submicron particles for various chemical, biological, medical and environmental applications.
Polymer electrolytes have received tremendous interest in the development of solid‐state batteries, but often fall short in one or more key properties required for practical applications. Herein, a ...rigid gel polymer electrolyte prepared by immobilizing a liquid mixture of a lithium salt and poly(ethylene glycol) dimethyl ether with only 8 wt% poly(2,2′‐disulfonyl‐4,4′‐benzidine terephthalamide) (PBDT) is reported. The high charge density and rigid double helical structure of PBDT lead to formation of a nanofibrillar structure that endows this electrolyte with stronger mechanical properties, wider temperature window, and higher battery rate capability compared to all other poly(ethylene oxide) (PEO)‐based electrolytes. The ion transport mechanism in this rigid polymer electrolyte is systematically studied using multiple complementary techniques. Li/LiFePO4 cells show excellent capacity retention over long‐term cycling, with thermal cycling reversibility between ambient temperature and elevated temperatures, demonstrating compelling potential for solid‐state batteries targeting fast charging at high temperatures and slower discharging at ambient temperature.
Incorporating lithium salt and poly(ethylene glycol) dimethyl ether (PEGDME) into a rigid‐rod nanofibrillar polymer matrix forms a gel polymer electrolyte that has superior thermomechanical properties over poly(ethylene oxide) (PEO), even when incorporating only 8% rigid‐rod polymer. Lithium metal battery testing shows reversible cycling between discharging at ambient temperature and charging at 80–120 °C, enabling fast recharging and reduced thermal management for, e.g., electric vehicle batteries.
•Relation between drag reduction and viscoelasticity of polymers is investigated.•Drag reduction correlates with extensional viscosity and Weissenberg number.•Drag reduction does not correlated with ...small-amplitude oscillatory shear.•For large degradation, extensional viscosity increases with decreasing strain rate.
The relation between the drag reduction (DR) performance of several water-soluble polymers and their viscoelastic properties was investigated. Polymers with a flexible molecular structure including three grades of polyacrylamides (PAM), and a polyethylene oxide (PEO) were investigated. Xanthan gum (XG) and carboxymethyl cellulose (CMC), each with a rigid molecular structure, were also considered. The rheology was characterized using steady shear-viscosity measurement, capillary break-up extensional rheometer (CaBER), and small-amplitude oscillatory shear measurement at the concentration of the drag-reduced solution. To isolate the effect of shear viscosity, the concentration of the polymers was adjusted to produce solutions with a similar shear viscosity at high shear rates. Using pressure drop measurements in a turbulent pipe flow, the DR of each polymer solution was determined. With identical high-shear-rate viscosities, the flexible PAM solutions resulted in an initial DR of 50–58%, while the initial DR of PEO was 44%, and the rigid polymers provided the least DR of 12%. The rigid polymers demonstrated negligible degradation of DR over a period of 2 h. Of the flexible polymers, PAM showed moderate degradation, while the DR of PEO quickly diminished after 20 min. Drag reduction correlated with extensional viscosity and Weissenberg number obtained from CaBER. A strong correlation was not observed between DR and the viscoelastic moduli obtained from small-amplitude oscillatory shear. The large mechanical degradation of PEO was associated with a continuous extensional thickening, in which extensional viscosity increased with decreasing strain rate until the filament broke up.
Solid polymer electrolytes (SPEs) based on polysiloxane having ion-conducting poly(ethylene oxide) (PEO) groups crosslinked with modified gallic acid from natural resources are prepared by thiol-ene ...click reaction for all-solid-state lithium metal battery applications. The effects of composition and crosslinking density on physical and electrochemical properties of the SPEs are systematically studied. The SPEs are found to be thermally and mechanically stable even at elevated temperature due to stable crosslinked polymer networks by modified gallic acid crosslinker. Furthermore, ionic conductivity of SPE based on 80 mol% of PEO group and 20 mol% of modified gallic acid crosslinker is found to be comparable to that of polymer electrolyte having a wax state. The formation and growth of lithium dendrites are effectively suppressed by the SPE due to its good compatibility with lithium metal anode and mechanical suppression effect. All-solid-state lithium metal battery is fabricated with SPE-integrated cathode and it is found that SPE exhibits superior cycle performance to conventional liquid electrolyte/separator system at 60 °C that is attributed to the good thermal stability and lithium dendrite-suppressing ability of the SPE.
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•Crosslinked solid polymer electrolytes (SPEs) are prepared using natural gallic acid.•The SPEs exhibit good thermal/electrochemical stability at elevated temperature.•Lithium dendrite growth is effectively suppressed by introducing the SPE.•All-solid-state lithium metal battery shows excellent cycle performance.
Membrane fouling is one of the most important challenges faced in membrane ultrafiltration (UF) operations. In this study, polyacrylonitrile-
graft-poly(ethylene oxide) (PAN-
g-PEO), an amphiphilic ...comb copolymer with a water-insoluble polyacrylonitrile (PAN) backbone and hydrophilic poly(ethylene oxide) (PEO) side chains, was used as an additive in the manufacture of novel PAN UF membranes. During casting, the PAN-
g-PEO additive segregates to form a PEO brush layer on all membrane surfaces, including internal pores. Wettability, pure water permeability, and resistance to irreversible fouling increased when either the amount of PAN-
g-PEO added to the membrane or the PEO content of the comb copolymer was increased. These trends were consistent with measured adhesion forces between the membranes and a carboxylated latex particle probe in an atomic force microscopy (AFM) analysis, and with the near-surface PEO coverage as determined by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) revealed further effects of additive incorporation on membrane morphology. In 24-h dead-end filtration studies, blend membranes prepared with 20
wt% PAN-
g-PEO (comb PEO content: 39
wt%) were found to resist irreversible fouling by 1000
ppm solutions of bovine serum albumin (BSA), sodium alginate, and humic acid, recovering the initial pure water flux completely by a pure water rinse, or a backwash in the case of humic acid. This exceptional anti-fouling performance holds promise for extending UF membrane lifetimes without need for aggressive cleaning procedures.
