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Thermally switchable ladder-like poly(silsesquioxane) (LPSQ) adhesives based on Diels–Alder reaction were prepared and utilized as reversible adhesion materials.

Anion exchange membranes prepared through cyclopolymerization of crosslinking of diallylammonium precursors were subjected to various physical, mechanical, and chemical stability property analysis for anion exchange membrane water electrolyzers.

Design of high energy density lithium storage materials is one of the everlasting issues in energy storage systems to realize a fully clean and sustainable energy grid. Here, 2,9-dimethyl quinacridone was selected as a precursor to prepare carbon-based electrode via low temperature heat-treatment process from 750 °C to 1050 °C. The pyro-polymerization of 2,9-dimethyl quinacridone induced a distinctive morphological transformation from rice husk-shaped 2,9-dimethyl quinacridone to carbon nanofibers. Electrode fabricated from pigment derived carbon nanofibers (PCNF) pyrolyzed at 750 °C maintained 878 mAh g-1 at a current density of 1 A g-1 and good Coulombic efficiency up to 98% after 1000 cycles. Furthermore, it delivered 337 mAh g-1 at a high current density of 25 A g-1. The superior performance was attributed to the stable structure of pristine 2,9-dimethyl quinacridone giving high thermal stability and crystallinity owing to well-defined π-π and hydrogen bonding interactions, thus rendering a stable microstructure with a large d-spacing of (002) plane of 3.580 A, as well as efficient surface redox reactions. Density functional theory calculations indicated that the large interlayer distance could facilitate fast lithium ion insertion/extraction because of a ∼38% lower energy barrier for lithium ion insertion than compared with graphite.

Reverse electrodialysis (RED) generates power directly by transforming salinity gradient into electrical energy. The ion transport properties of the ion-exchange membranes need to be investigated deeply to improve the limiting efficiencies of the RED. The interaction between “counterions” and “ionic species” in the membrane requires a fundamental understanding of the phase separation process. Here, we report on sulfonated poly(vinylidene fluoride-co-hexafluoropropylene)/graphitic carbon nitride nanocomposites for RED application. We demonstrate that the rearrangement of the hydrophilic and hydrophobic domains in the semicrystalline polymer at a nanoscale level improves ion conduction. The rearrangement of the ionic species in polymer and “the functionalized nanosheet with ionic species” enhances the proton conduction in the hybrid membrane without a change in the structural integrity of the membrane. A detailed discussion has been provided on the membrane nanostructure, chemical configuration, structural robustness, surface morphology, and ion transport properties of the prepared hybrid membrane. Furthermore, the RED device was fabricated by combining synthesized cation exchange membrane with commercially available anion exchange membrane, NEOSEPTA, and a maximum power density of 0.2 W m−2 was successfully achieved under varying flow rates at the ambient condition.

BackgroundPolymerase chain reaction (PCR) is an important means by which to study the urine microbiome and is emerging as possible alternative to urine cultures to identify pathogens that cause urinary tract infection (UTI). However, PCR is limited by its inability to differentiate DNA originating from viable, metabolically active versus non-viable, inactive bacteria. This drawback has led to concerns that urobiome studies and PCR-based diagnosis of UTI are confounded by the presence of relic DNA from non-viable bacteria in urine. Propidium monoazide (PMA) dye can penetrate cells with compromised cell membranes and covalently bind to DNA, rendering it inaccessible to amplification by PCR. Although PMA has been shown to differentiate between non-viable and viable bacteria in various settings, its effectiveness in urine has not been previously studied. We sought to investigate the ability of PMA to differentiate between viable and non-viable bacteria in urine.MethodsVarying amounts of viable or non-viable uropathogenic E. coli (UTI89) or buffer control were titrated with mouse urine. The samples were centrifuged to collect urine sediment or not centrifuged. Urine samples were incubated with PMA and DNA cross-linked using blue LED light. DNA was isolated and uidA gene-specific PCR was performed. For in vivo studies, mice were inoculated with UTI89, followed by ciprofloxacin treatment or no treatment. After the completion of ciprofloxacin treatment, an aliquot of urine was plated on non-selective LB agar and another aliquot was treated with PMA and subjected to uidA-specific PCR.ResultsPMA’s efficiency in excluding DNA signal from non-viable bacteria was significantly higher in bacterial samples in phosphate-buffered saline (PBS, dCT=13.69) versus bacterial samples in unspun urine (dCT=1.58). This discrepancy was diminished by spinning down urine-based bacterial samples to collect sediment and resuspending it in PBS prior to PMA treatment. In 3 of 5 replicate groups of UTI89-infected mice, no bacteria grew in culture; however, there was PCR amplification of E. coli after PMA treatment in 2 of those 3 groups.ConclusionWe have successfully developed PMA-based PCR methods for amplifying DNA from live bacteria in urine. Our results suggest that non-PMA bound DNA from live bacteria can be present in urine, even after antibiotic treatment. This indicates that viable but non-culturable E. coli can be present following treatment of UTI, and may explain why some patients have persistent symptoms but negative urine cultures following UTI treatment.

Hydrogen fuel cells are attractive devices for automotive applicationswith benefits such as extended driving range, swiftrefuelling time and clean exhausts1. Although passenger fuelcell electric vehicles have been successfully launched, further technologicalinnovations are needed for the next-generation fuel cellplatform to evolve for heavy-duty vehicles (HDVs)2–4. One of thedifficulties encountered in HDV operation is adequate heat rejection.As current low-temperature polymer electrolyte membranefuel cells (LT-PEMFCs) operate at ~80 °C, the waste heat needs tobe rejected across a 40 °C temperature difference5. Heat rejection inHDVs is facilitated by high cell voltage at rated power (≥0.76 V)6,which translates to lower power densities (100 °C due to high water partial vapour pressure10.Therefore, extensive research efforts to develop polymerelectrolytes for high-temperature polymer electrolyte membranefuel cells (HT-PEMFCs) have been undertaken over the pastdecade. HT-PEMFCs typically use phosphoric acid-doped polybenzimidazole(PA-PBI)11–13. However, PA-PBI-based fuel cells arechallenging to operate below 140 °C or during frequent startup/shutdown14 without suffering a loss of phosphoric acid, which makesHT-PEMFCs unfavourable for automotive applications. We previouslyreported that HT-PEMFCs based on quaternary ammoniumbiphosphate ion-pair coordination (ion-pair HT-PEMFCs) exhibitedexcellent phosphoric acid retention in the temperature range80–200 °C, but the performance of the ion-pair HT-PEMFCs waspoor15–17. Therefore, further performance improvement is requiredfor the ion-pair HT-PEMFCs to be commercially viable for HDVapplications18 (Table 1).Here we report on a protonated phosphonated ionomer thatincreases proton conductivity more than an order of magnitudecompared with a non-protonated phosphonated ionomer. We showexperimental and theoretical evidence of the protonation of phosphonicacids that is distinct from the hydrogen bonding of phosphonicacids18. Based on this concept, we designed protonatedphosphonic acid electrodes that enable remarkable power densityand are well suited for HDV fuel cells.

The interaction energy of base-acid plays a key role in acid retention of phosphoric acid (PA)-doped polymer electrolytes under fuel cell operating conditions. Here, we investigate the energetics of proton-accepting and hydroxide-donating organic bases using density functional theory calculations. Because of their weak basicity, proton-accepting organic bases such as benzimidazole have relatively low interaction energy with the acid in the absence of water (15.3-28.0 kcal mol-1). Energetics of the proton-accepting base-PA complex increases by adding water, indicating that the interactions in the base-acid complex strengthen in the presence of water. On the other hand, hydroxide-donating organic bases, such as tetramethylammonium hydroxide, have high interaction energy with PA (∼110 kcal mol-1), which remains high in the presence of water. The chemical shifts of 31P NMR support the energetics of the base-acid complexes. This study further discusses the benefit of incorporating hydroxide-donating organic bases into the polymeric structure over proton-accepting bases as a way to increase acid retention.

Non-aqueous lithium-ion redox flow batteries (Li-RFBs) have recently garnered much interest because of their high operating voltage and energy density. Albeit these outstanding advantages, challenges, such as poor cyclability and efficiency, still remain in employing the practical application. In an attempt to address these problems, a series of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and TEMPO derivatives catholytes were prepared and investigated as redox-active materials. Electrochemical evaluation exhibited that the introduction of polar and electron-withdrawing substituents to TEMPO was able to enhance the rate capability and cycling stability, when compared to those with the neat TEMPO. Extensive analysis of the electrochemical properties revealed that the electrophilic heteroatom stabilized the radical as well as alleviated the catholyte degradation. Overall, a careful selection of redox-active species demonstrates great promise in improving the current redox flow battery technology.

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/Nylon 66 blends have been considered as the potential heat resistant engineering plastics with high mechanical toughness and flame retardancy, suitable for high temperature applications. However, incompatibility between PPE and Nylon 66 and poor thermal stability of Nylon 66 degrade mechanical toughness and flame retardancy. In this work, for the first time, the PPE/Nylon 66 blends with high mechanical toughness and flame retardancy simultaneously have been prepared through newly synthesized compatibilizer of PPE grafted with fumaric acid (PPE-g-FA) and environmental-friendly non-halogen organic phosphinate flame retardant. The PPE/Nylon 66 blend achieved not only V0 grade flame retardancy with the help of improved fire resistance through the solid phase reaction of non-halogenic flame retardant, but also large impact strength larger than 10 kJ/m2 due to the strong compatibility of PPE-g-FA.

Polymerase chain reaction (PCR) is an important means by which to study the urine microbiome and is emerging as possible alternative to urine cultures to identify pathogens that cause urinary tract infection (UTI). However, PCR is limited by its inability to differentiate DNA originating from viable, metabolically active versus non-viable, inactive bacteria. This drawback has led to concerns that urobiome studies and PCR-based diagnosis of UTI are confounded by the presence of relic DNA from non-viable bacteria in urine. Propidium monoazide (PMA) dye can penetrate cells with compromised cell membranes and covalently bind to DNA, rendering it inaccessible to amplification by PCR. Although PMA has been shown to differentiate between non-viable and viable bacteria in various settings, its effectiveness in urine has not been previously studied. We sought to investigate the ability of PMA to differentiate between viable and non-viable bacteria in urine.Varying amounts of viable or non-viable uropathogenicPMA's efficiency in excluding DNA signal from non-viable bacteria was significantly higher in bacterial samples in phosphate-buffered saline (PBS, dCWe have successfully developed PMA-based PCR methods for amplifying DNA from live bacteria in urine. Our results suggest that non-PMA bound DNA from live bacteria can be present in urine, even after antibiotic treatment. This indicates that viable but non-culturable

Fuel cells are electrochemical devices with high energy efficiency expected to be applied economically and eco-friendly across various energy sectors. Low-temperature polymer electrolyte membrane fuel cells (LT-PEMFCs) using Nafion operates at a relatively low operating temperature (60-80°C) and a full hydration condition. HT-PEMFC is operable at high temperatures (140-180°C), but requires anhydrous conditions to avoid loss of doped phosphoric acid (PA). In this study, polymer membranes designed through with intrinsic microporosity were synthesized through super acid polycondensation. We demonstrated that high proton conductivity (106.33 mS cm-1 at 180℃) is obtained by forming phosphoric acid filled ion-channels within the interconnected microporous structure. Moreover, ion-pair coordinated PIMs are fabricated by methylation of PIMs to improve PA retention even under humidified conditions. It is suggested that the water tolerance of ion-pair coordinated PIMs is improved and can be operated under various conditions regardless of humidification and operating temperature.

INTRODUCTION To examine the impact of COVID-19 pandemic on the presentation, management and outcome of testicular torsion at our institution.A retrospective review of a prospectively maintained testicular torsion database was performed. Patients ≤ 18 years of age evaluated in our emergency room between 3/11/2020 to 10/1/2020 (during-COVID-19) and the same period in 2018 and 2019 (pre-COVID-19) with US diagnosed and OR confirmed testicular torsion were included. Basic demographics, timing of presentation, referral rate, time to OR and orchiectomy rate were extracted and compared. P0.05 was considered statistically significant.A total of 82 torsions were included in the study; 55 pre-COVID-19 and 27 during-COVID-19. The incidence of testicular torsion remained the same; 3.93 cases/month pre-COVID-19 versus 3.86 cases/month during-COVID-19 (p = 0.791). However, there were significantly fewer delayed (24 hours) presentations (11.1% versus 45.5% , p = 0.003), shorter time from onset of symptoms to presentation (median 15.5 hours versus 8 hours, p = 0.001), and a lower but not statistically significant overall orchiectomy rate (33.3% versus 50.9% p = 0.1608) during-COVID-19. Among those presenting acutely with torsion (24 hours from onset), no statistical differences were found in the median time from US diagnosis to OR, from ED to OR, referral rate, or orchiectomy rate between the two groups. Lastly, SARS-CoV2 testing did not delay median time from ED to OR.There was a notably less delayed presentation of testicular torsion and shorter ischemia time on presentation during-COVID, however, no significant change of time to OR or orchiectomy rate in those with acute testicular torsion were observed.

Fuel cells operating at above 100 °C under anhydrous conditions provide an ideal solution for the heat rejection problem of heavy-duty vehicle applications. Here, we report protonated phosphonic acid electrodes that remarkably improve fuel cell performance. The protonated phosphonic acids are comprised of tetrafluorostyrene phosphonic acid and perfluorosulfonic acid polymers in which a proton of the perfluorosulfonic acid is transferred to the phosphonic acid to enhance the anhydrous proton conduction of fuel cell electrodes. By implementing this material into fuel cell electrodes, we obtained a fuel cell exhibiting a rated power density of 780 milliwatts per square centimeter at 160 °C, with minimal degradation during 2,500 hours of operation, and 700 thermal cycles from 40 to 160 °C under load.

Objective To inform the development of strategies to improve adherence to guidelines, we sought to identify characteristics of pediatric patients with nephrolithiasis associated with completing 24-hour urine analyses. Materials and Methods We performed a retrospective cohort study of patients with nephrolithiasis aged 3-18years treated in a large pediatric healthcare system from May 2012 to May 2017. Multivariable Cox models were fit to estimate the association between patient characteristics and completion of a 24-hour urine analysis. Results Among 623 patients, 317 (50.9%) completed a 24-hour urine collection. Median age was 14.4years (interquartile range [IQR] 10.5, 16.3). In adjusted analyses, age at diagnosis (hazard ratio [HR] 1.03; 95% confidence interval [CI] 1.01-1.07), renal colic on presentation (HR 1.72; 95% CI 1.15-2.58), and family history of nephrolithiasis (HR 1.50; 95% CI 1.17-1.93) were associated with an increased likelihood of completion of a 24-hour urine. Public/government assistance insurance (HR 0.68; 95% CI 0.48-0.96) was associated with decreased likelihood of completing a 24-hour urine. Conclusion Patients who had prior painful experiences with stones (renal colic), and potential better understanding of nephrolithiasis (family history, older age on presentation) were more likely to complete a 24-hour urine. Those patients with public insurance/government assistance were less likely to complete a 24-hour urine. These results can be used to develop strategies to improve pediatric patients’ adherence to completing 24-hour urine collections.

Silica nanoparticles were chemically grafted onto a porous polyethylene separator to improve the adhesion strength, thermal stability, and electrochemical performance of a polyolefin separator. A surface activation via UVO plasma treatment, followed by silane hybridization yielded a polymeric binder-free, thin coating of SiO2 nanoparticles onto the separator. The chemical grafting provided a much stronger adhesive strength (> 2.5 N/cm), reduced thermal shrinkage (

Anode ionomers of alkaline membrane fuel cells (AMFCs) play a critical role in hydrogen and water transport thus affecting cell performance and durability. Here, we modified a quaternized poly(biphenyl alkylene) ionomer with two chemical structural variations to increase hydrogen access to the AMFC anode: first, we introduced the symmetric dimethyl groups in the polymer backbone to increase polymer fractional free volume. Second, we replaced hydroxide-conducting alkyl trimethylammonium with alkyl triethylammonium to reduce cation–hydroxide–water co-adsorption on the hydrogen oxidation catalyst to increase hydrogen access to the co-adsorbed layer. We compared the performance benefits of the two structural variations through operating AMFCs under H2/O2 conditions. The membrane electrode assembly employing the modified poly(biphenyl alkylene) ionomer at the anode exhibited >1500 mW cm−2 peak power density at 80 °C with stable short-term durability (>100 h) under a constant current density of 0.6 A cm−2. This study provides an essential insight into designing anode ionomer of highly performing AMFCs.

Acid retention of phosphoric acid (PA)-doped proton exchange membranes (PEMs) is one of the critical factors that determine the durability of high temperature PEM fuel cells. However, the mechanism of PA loss in the PEMs in the presence of water is obscure in the context of the energetics of the PA cluster. Here, we study the energetics of PA–benzimidazole acid–base and biphosphate–ammonium ion pairs using density functional theory calculations and 31P NMR experiments to propose a novel PA loss mechanism. The results suggest that the removal of the PA from the membrane does not occur due to the strong interaction of PA–water, but due to the incapability of the base polymers to hold the water and PA beyond a certain level. Significantly higher interaction in the biphosphate–ammonium ion pair shifts the equilibrium PA composition in the PA cluster to higher values, which minimizes the PA loss in the presence of water. Introducing high interaction between base, water, and PA molecules provides a path for better high temperature PEM design with excellent acid retention capabilities.

Carbon molecular sieve (CMS) membranes are a promising candidate for natural gas processing due to their peculiar pore structure-induced excellent separation performance. Formulating ultrathin, defect-free CMS hollow fiber membranes is, however, still challenging due to damage on porous sub-structures induced by thermal relaxation of polymer chains during pyrolysis. Herein, we report a new methodology enabling high separation performance and good plasticization resistance in CMS fiber membranes by uniform integration of double-stranded polysilsesquioxanes into the polyimide matrix. Our polyimide/ladder-structured polysilsesquioxane CMS fibers substantially enhanced CO2 permeance by as much as 546% compared to the precursor fiber analogues due to the thin molecular sieve selective layer. Also, poly(dimethylsiloxane) coating delayed physical aging, still showing a high CO2 permeance of 354 GPU with CO2/CH4 selectivity of 56 after 72 days of aging. Furthermore, they exhibited excellent plasticization resistance up to a CO2 partial pressure of 13.2 bar with CO2/CH4 separation factor of 74 for an equimolar CO2/CH4 feed mixture.

Healthcare disparities have been shown to impact outcomes of various acute pediatric conditions. We sought to examine the impact of race, ethnicity and insurance status on the presentation, management and outcome of testicular torsion.A retrospective review of a prospectively maintained testicular torsion database was performed. Patients ≤18 years of age evaluated in our pediatric institution's emergency room between April 2016-April 2020 with US diagnosed and OR confirmed testicular torsion were included. Basic demographics, timing of presentation, referral rate, time to OR and orchiectomy rate were extracted and compared. P 0.05 was considered statistically significant.A total of 206 patients were included. 114 (56.2%) were Black or African American (Black/AA), 43 were (21.2%) Hispanic/Latino, 22 (10.8%) were Caucasian, and 24 (11.8%) were designated as Other races. Ninety-eight (48.3%) patients had Medicaid, 90 (44.3%) had private insurance, and 15 (7.4%) patients were uninsured. Sixty-eight (33.0%) presented in a delayed fashion (24 h). Compared to the Caucasian patients, Black/AA patients were 2.1 years (95% CI: 0.5, 3.8; P = 0.010) older at the time of presentation. When compared to those with Medicaid insurance, uninsured patients had 6.26 times (95% CI: 1.58, 41.88; P = 0.021) higher odds to be referred from an outside hospital for management. In those patients presenting acutely (24 h, N = 138), there were no significant differences in the odds of orchiectomy for Black/AA or Hispanic/Latino patients when compared to Caucasian patients, however, the odds of orchiectomy in Other races (non-Caucasian, non-Black/AA, non-Hispanic/Latino) was significantly higher (OR: 10.38; 95% CI: 1.13, 246.96; P = 0.049). While the mean time in minutes from ED to OR was longer in those with Medicaid insurance (141 vs 125.4 private vs 115 uninsured, p = 0.042), this did not impact orchiectomy rate (39.8% vs 40.9% vs 46.7%, p = 0.88).We found no differences in the orchiectomy rates by race with the exception of a higher rate in the diverse and heterogeneous Other race (non-Caucasian, non-Black/AA, non-Hispanic/Latino) group. Those uninsured had a higher referral rate highlighting the potential existence of disparities for those uninsured and the need for further investigation.

A series of UV-curable hybrid composite blends containing a carboxylic acid functionalized polyimidewith varying amounts of high molecular weight (~1 K) PEG-grafted ladder-structured polysilsesquioxanes copolymerized with methacryl groups were fabricated and their structural, thermal, mechanical, and surface properties characterized. At a composite weight ratio of polyimide above 50 wt.%, a stark shift from amorphous to crystalline polyethylene glycol (PEG) phases were observed, accompanied by a drastic increase in both surface moduli and brittleness index. Moreover, fabricated composites were shown to have a wide range water contact angle, 9.8&deg, &ndash, 73.8&deg, attesting to the tunable surface properties of these amphiphilic hybrid polymer composites. The enhanced mechanical properties, combined with the utility of tunable surface hydrophilicity allows for the possible use of these hybrid polymer composites to be utilized as photosensitive polyimide negative photoresists for a myriad of semiconductor patterning processes.

Modern electrochemical energy conversion devices require more advanced proton conductors for their broad applications. Phosphonated polymers have been proposed as anhydrous proton conductors for fuel cells. However, the anhydride formation of phosphonic acid functional groups lowers proton conductivity and this prevents the use of phosphonated polymers in fuel cell applications. Here, we report a poly(2,3,5,6-tetrafluorostyrene-4-phosphonic acid) that does not undergo anhydride formation and thus maintains protonic conductivity above 200 °C. We use the phosphonated polymer in fuel cell electrodes with an ion-pair coordinated membrane in a membrane electrode assembly. This synergistically integrated fuel cell reached peak power densities of 1,130 mW cm−2 at 160 °C and 1,740 mW cm−2 at 240 °C under H2/O2 conditions, substantially outperforming polybenzimidazole- and metal phosphate-based fuel cells. Our result indicates a pathway towards using phosphonated polymers in high-performance fuel cells under hot and dry operating conditions. Phosphonated polymers have been proposed as anhydrous proton conductors for fuel cells but anhydride formation of phosphonic acid functional groups lowers conductivity. A synergistically integrated phosphonated poly(pentafluorostyrene) is shown to maintain high protonic conductivity above 200 °C.

A series of ladder-like polysilsesquioxanes (LPSQs) containing the UV-curable methacryoxypropyl (MA) and different organic functional (R) groups (propyl, hexyl, cyclohexyl, phenyl or naphthyl) at the fixed MA/R molar ratio were synthesized as hard coating materials. The LPSQ hard coating films prepared by a simple UV curing process exhibited excellent optical transparency in the visible light range. X-ray diffraction analysis of the LPSQ films characterized how their intermolecular chain-to-chain distance and thus chain packing density varied according to the organic functional group. In addition, the hardness, elastic modulus and scratch resistance of the LPSQ films were evaluated by nanoindentation and nanoscratch tests. Although the mechanical properties of the LPSQ films were affected by both the chain rigidity of the organic functional group and the chain packing density of the siloxane backbones, chain rigidity played the dominant role in determining their mechanical robustness. Hence, despite its lowest chain packing density, the LPSQ film with the naphthyl group exhibited the best mechanical properties due to its high chain rigidity derived from the increased aromaticity of the naphthyl group. This study suggests the key factor when designing mechanically durable, scratch resistant hard coating films is the chain rigidity of the film network.

An effective method to enhance the durability of polymer electrolyte membrane fuel cells (PEMFCs) is reported. PEMFC performance loss is mitigated by exposing the electrodes of fuel cells to dry nitrogen gas periodically at high temperature. This method extends the lifetime of fuel cells significantly compared to their non-treated counterparts. The impact of treatment temperature and exposure time on PEMFC durability is reported, using potential cycling accelerated stress tests. The enhanced durability is attributed to the suppression of “ionomer relaxation” that occurs under the nearly water saturated operating conditions of a PEMFC cathode.

This paper reports the recycling of flexible printed circuit board (FPCB) waste through carbonization of polyimide by dual pyrolysis processes. The organic matter was recovered as pyrolyzed oil at low temperatures, while valuable metals and polyimide-derived carbon were effectively recovered through secondary high temperature pyrolysis. The major component of organics extracted from FPCB waste comprised of epoxy resins were identified as pyrolysis oils containing bisphenol-A. The valuable metals (Cu, Ni, Ag, Sn, Au, Pd) in waste FPCB were recovered as granular shape and quantitatively analyzed via ICP-OES. In attempt to produce carbonaceous material with increased degree of graphitization at low heat-treatment conditions, the catalytic effect of transition metals within FPCB waste was investigated for the efficient carbonization of polyimide films. The morphology of the carbon powder was observed by scanning electron microscopy and graphitic carbonization was investigated with X-ray analysis. The protocols outlined in this study may allow for propitious opportunities to salvage both organic and inorganic materials from FPCB waste products for a sustainable future.

A new method for enhancing condensable gas-induced plasticization resistance of aromatic polyimides (PIs) as well as increasing the flux of gas penetrants with negligible selectivity loss was demonstrated via a so-called bromination/debromination-induced thermal crosslinking. Our newly developed crosslinking approach essentially loosened the polymeric chain packing of 6FDA-Durene PIs by forming ethylene crosslinking bonds, while retaining its rigid PI backbone. As the degree of crosslinking increased, the permeability increased with trivial selectivity loss. Notably, the 75% bromination/debromination-induced crosslinked PI membranes drastically improved CO2 and C3H6 permeabilities by as much as 157% and 172%, respectively, compared to those of the pristine-PI analogs due to the debromination-induced free volume enhancement, while maintaining good selectivity due to the crosslinked ethylene bridges. As a result, outstanding separation performances for CO2/N2, CO2/CH4 and C3H6/C3H8 gas pairs have been obtained, and most importantly, a high tolerance to CO2- or C3H6-induced plasticization was observed up to CO2 or C3H6 pressure of 24 and 10 atm, respectively. Our current crosslinking approach can be extended to industrially attractive hollow fiber forms of various aromatic PIs for high plasticization resistance as well as high flux.

Pourable and room temperature flowable ladder-structured polysilsesquioxanes were synthesized and applied as functional optical hard coatings. Organic functional group type (propyl, hexyl, octyl, dodecyl) and their copolymer composition with UV-curable methylacryloxypropyl group were selected as to control both pre-cured viscosity and final mechanical properties independent of molecular weight. Ladder-structured polysilsesquioxanes with longer alkyl side chains exhibited higher fluidity and flexibility while maintaining its optical property and mechanical strength. The solvent-free processability of our synthesized materials along with their superior optical and mechanical properties over commercial solvent-based hard coatings suggest the high value of our hybrid materials for the coatings industry.

To data, combination of Pt-based bimetallic nanocrysatals and the graphene support have significantly contributed to enhance the oxygen reduction reaction (ORR) performance relative to electrocatalysts based on monometallic Pt nanoparticles (NPs) primarily due to the unique ligand effects and benefits of the carbon support. In this study, we propose a new structure of bimetallic electrocatalysts to realize the synergistic effects on the ORR performance through effective integration of the fine-sized Pt NPs, PdPt bimetallic nanocrystals, and non-covalently functionalized graphene with ionic polymers. The facile wet-chemical methods were applied to synthesize fine-sized (2–5 nm) spherical Pt NPs doped large-sized (20–50 nm) non-spherical PdPt bimetallic NPs on the electronically negative ionic polymer-functionalized graphene support (Pt-on-PdPt/fG). This Pt-on-PdPt/fG with synergistic effects based on enlarged active surface area, ligand, and interfacial linking effects, exhibits substantially enhanced ORR activity (specific activity: 1.89 mA c m Pt − 2 at 0.9 VRHE) and durability in comparison to the commercial Pt/C (specific activity: 0.23 mA c m Pt − 2 at 0.9 VRHE). To this end, the effective integration of newly designed fine-sized Pt NPs doped bimetallic nanocrystals and unique graphene supports with the well-interactive ability could be a good platform to develop the advanced electrocatalysts for the efficient ORR.

Thermally curable hybrid ionogel electrolytes consisting of epoxy-functionalized POSS, amine-terminated polypropylene glycol, and ionic liquid electrolyte, 1 M LiTFSI in BMPTFSI were fabricated to give ionic conducting epoxy networks with cubic inorganic star networks crosslinked with lithium ion dissociating polypropylene glycol linkers. Characterization of these hybrid ionogels revealed high ion conduction, exceptional thermal stability, and electrochemical stability. Lithium ion capacitors fabricated with these hybrid ionogels revealed exceptional performance on par with the neat liquid ionic liquid electrolyte, and far superior over ionogels fabricated with conventional organic crosslinkers, due to the mechanical robustness and lithium ion dissociative character imparted by the POSS and PPG functionalities.

Developing polymeric membranes with propylene/propane separation performance surpassing the upper bound has been received much attention. Herein, a highly controlled thermal treatment process yielding microporous polyimide membranes made from dense brominated-polyimide membrane precursor via thermal debromination/cross-linking approach is demonstrated. We showed that facile thermal treatment could generate a narrow size distribution of micro-voids as well as covalent linkages between inter/intra polymer chains while the polyimide backbone structure remained intact. The thermally treated membranes were well-characterized by FTIR, TGA, WAXD, solid-state 13C NMR and N2 adsorption/desorption isotherm. Single gas propylene/propane (C3H6/C3H8) separation performance greatly improved in terms of both selectivity and permeability, surpassing the trade-off line while maintaining flexible membrane properties. A thermal cross-linking treatment at 380 °C for 5 h exhibited the best C3H6 permeability of 84.70 barrer and C3H6/C3H8 selectivity of 14.6 with high plasticization resistance.

In this study, a liquid state sulfur polymer (LSP) was employed as asphalt pavement materials. The LSP/epoxy asphalt (LSPA) was easily fabricated by mixing LSP and epoxy resin at room temperature. The workability of as-mixed LSP/epoxy mixture was explored by controlling the ratio of epoxy. The asphalt mixture with the epoxy content below 50 wt% exhibited reliable flowability above approximately 12.5 cm. The solidification of LSP was successfully accompanied by simultaneous curing of epoxy. For practical application of pavement on road, the Marshall stability, indirect tensile strength and wheel tracking test were performed. The Marshall stability and indirect tensile strength of the LSPA exhibited an approximate 2-fold increase compared to neat asphalt. Moreover, exceptional durability of the LSPA was achieved through the controllable crushed depth of the pavement under wheel passes of 25,000 cycles. For practical repairing test on the road, the LSPA was cast on a pothole prepared on asphalt road. Our as-cast asphalt materials were suitable to heal potholes with seamless interface and the hardening was accomplished within a very short time of 1 h. The hardened LSPA exhibited excellent adhesion strength of approximately 1.95 MPa, enabling the elimination of gaps arising from traffic cycles and climate variation.

A series of multi-crosslinkable, self-healing, ladder-structured polysilsesquioxane inorganic-organic hybrid materials were developed to enhance the mechanical properties through tandem UV-curing and Diels-Alder chemistry. The introduction of UV-curable acryl- or epoxy groups allowed for a higher degree of crosslink density while bringing the inorganic backbones closer together for highly efficient self-healing properties, all with a singular material as the ternary organic functional groups consisting of UV-curable function, diene, and dienophile were tethered to the well-defined inorganic backbone. Exceptional thermal stability (>400 °C), optical transparency (>95%), solution processability, as well as robust surface mechanical properties in both bulk (pencil hardness 6H) and nanoscale (elastic modulus > 9 GPa), properties which can be adroitly recovered through mild and rapid thermal treatment hold great promise for next generation hybrid smart coating materials for application in optoelectronic devices.

Most inorganic nucleating agents for poly(ethylene terephthalate) (PET) have limited nucleating ability due to poor compatibility with PET. Polyhedral oligomeric silsesquioxanes (POSS) is a type of cage-shaped organic/inorganic hybrid nanoparticles with three different particle sizes: octameric (T8), decameric (T10), and dodecameric (T12). POSS is considered as a promising nucleating agent for PET because the inorganic moieties contribute to high thermal stability and nucleation and the organic moieties can be tethered to PET chains. In contrast to T8 POSS, the nucleation ability of T12 POSS for PET has been poorly reported. In this study, our newly synthesized aminopropyl functionalized T12 POSS (A-POSS) is proposed as a potential nucleating agent for PET. The amine group of A-POSS is able to be chemically conjugated to PET chains, thereby giving a more homogeneous dispersion of T12 POSS in PET than non-functional T12 Phenyl POSS (N-POSS). Its PET composites gave a ∼1.2 fold higher crystallization temperature and ∼2.7 fold higher shear-induced crystallization rate over pristine PET. Such nucleating effects for PET is more effective than those of non-functional T12 POSS and the more widely studied T8 POSS. This strategy is potentially beneficial for the high-shear melt processes of PET such as spinning and film extrusion.

Heteroleptic ruthenium-complexed ladder-like structured polysilsesquioxane (LPSQ-Ru) was synthesized by post coordination reaction of bidentate ligand side chains in LPSQ with reactive Ru(II) complexes, which was well characterized by 1H and 29Si NMR, FT-IR, and spectroscopic techniques. The photophysical properties of LPSQ-Ru were examined by UV and PL analyses in both solution and solid states, comparing to analogous polymers of ruthenium-complexed polystyrene (PS-Ru). Obtained absorptions of LPSQ-Ru and PS-Ru were broadened ranging from 390-490 nm regardless of the states. However, LPSQ-Ru exhibited higher and shaper PL emission spectrum in comparison to that of PS-Ru, particularly in the solid state, because Ru-complexes in LPSQ were much effectively isolated, preventing their aggregations due to the rigid double strained siloxane backbone. This extinguished photophysical property in LPSQ-Ru kept after intensive thermal treatment at 250 °C for 90 min, which was not achieved in PS-Ru (~5-fold decrease). These differences originated from the backbone structures were also appeared in electrochemical properties in the solid states.

A multifunctional crosslinkable and ionic-group functionalized ladder-like polysilsesquioxane was synthesized and utilized for the fabrication of hybrid ionogels for lithium ion batteries. The ionic-group functionalized ladder-like polysilsesquioxane combined the synergistic effects of hybrid materials in improving the thermal stability of conventional battery electrolytes, whilst maintain facile solution processability and chemically crosslinkable function in ionic conducting ionic liquid electrolyte media. Fabricated iongel electrolytes exhibiting exceptional thermal stability, mechanical properties, high ionic conductivity, and electrochemical stability. Lithium ion batteries fabricated with the hybrid ionic ladder-like polysilsesquioxane ionogels exhibited initial discharge capacities on par with neat liquid electrolytes, good rate performance, as well as stable cyclability and excellent Coulombic efficiency.