Hydrocarbon-Based Composite Membrane Using LCP-Nonwoven Fabrics for Durable Proton Exchange Membrane Water Electrolysis.

A new hydrocarbon-based (HC) composite membrane was developed using liquid crystal polymer (LCP)-nonwoven fabrics for application in proton exchange membrane water electrolysis (PEMWE). A copolymer of sulfonated poly(arylene ether sulfone) with a sulfonation degree of 50 mol% (SPAES50) was utilized as an ionomer for the HC membranes and impregnated into the LCP-nonwoven fabrics without any surface treatment of the LCP. The physical interlocking structure between the SPAES50 and LCP-nonwoven fabrics was investigated, validating the outstanding mechanical properties and dimensional stability of the composite membrane in comparison to the pristine membrane. In addition, the through-plane proton conductivity of the composite membrane at 80 °C was only 15% lower than that of the pristine membrane because of the defect-free impregnation state, minimizing the decrease in the proton conductivity caused by the non-proton conductive LCP. During the electrochemical evaluation, the superior cell performance of the composite membrane was evident, with a current density of 5.41 A/cm2 at 1.9 V, compared to 4.65 A/cm2 for the pristine membrane, which can be attributed to the smaller membrane resistance of the composite membrane. From the results of the degradation rates, the prepared composite membrane also showed enhanced cell efficiency and durability during the PEMWE operations.

Recapitulated Crosstalk between Cerebral Metastatic Lung Cancer Cells and Brain Perivascular Tumor Microenvironment in a Microfluidic Co-Culture Chip.

Non-small cell lung carcinoma (NSCLC), which affects the brain, is fatal and resistant to anti-cancer therapies. Despite innate, distinct characteristics of the brain from other organs, the underlying delicate crosstalk between brain metastatic NSCLC (BM-NSCLC) cells and brain tumor microenvironment (bTME) associated with tumor evolution remains elusive. Here, a novel 3D microfluidic tri-culture platform is proposed for recapitulating positive feedback from BM-NSCLC and astrocytes and brain-specific endothelial cells, two major players in bTME. Advanced imaging and quantitative functional assessment of the 3D tri-culture model enable real-time live imaging of cell viability and separate analyses of genomic/molecular/secretome from each subset. Susceptibility of multiple patient-derived BM-NSCLCs to representative targeted agents is altered and secretion of serpin E1, interleukin-8, and secreted phosphoprotein 1, which are associated with tumor aggressiveness and poor clinical outcome, is increased in tri-culture. Notably, multiple signaling pathways involved in inflammatory responses, nuclear factor kappa-light-chain-enhancer of activated B cells, and cancer metastasis are activated in BM-NSCLC through interaction with two bTME cell types. This novel platform offers a tool to elucidate potential molecular targets and for effective anti-cancer therapy targeting the crosstalk between metastatic cancer cells and adjacent components of bTME.

Aluminum Diethylphosphinate-Incorporated Flame-Retardant Polyacrylonitrile Separators for Safety of Lithium-Ion Batteries.

Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and flame-retardant separator in high-performance and safe lithium-ion batteries (LIBs). ADEP is phosphorus-rich, thermally stable, and flame retardant, and it can effectively suppress the combustibility of PAN nanofibers. Nanofibrous membranes were obtained by electrospinning, and the content of ADEP varied from 0 to 20 wt%. From the vertical burning test, it was demonstrated that the flame retardancy of the composite membranes was enhanced when more than 5 wt% of ADEP was added to PAN, potentially increasing the safety level of LIBs. Moreover, the composite membrane showed higher ionic conductivity and electrolyte uptake (0.83 mS/cm and 137%) compared to those of commercial polypropylene (PP) membranes (Celgard 2400: 0.65 mS/cm and 63%), resulting from interconnected pores and the polar chemical composition in the composite membranes. In terms of battery performance, the composite membrane showed highly stable electrochemical and heat-resistant properties, including superior discharge capacity when compared to Celgard 2400, indicating that the PAN/ADEP composite membrane has the potential to be used as a heat-resistant and flame-retardant separator for safe and high-power LIBs.

Electrically Conducting and Mechanically Strong Graphene-Polylactic Acid Composites for 3D Printing.

The advent of 3D printing has had a disruptive impact in manufacturing and can potentially revolutionize industrial fields. Thermoplastic materials printable into complex structures are widely employed for 3D printing. Polylactic acid (PLA) is among the most promising polymers used for 3D printing, owing to its low cost, biodegradability, and nontoxicity. However, PLA is electrically insulating and mechanically weak; this limits its use in a variety of 3D printing applications. This study demonstrates a straightforward and environment-friendly method to fabricate conductive and mechanically reinforced PLA composites by incorporating graphene nanoplatelets (GNPs). To fully utilize the superior electrical and mechanical properties of graphene, liquid-exfoliated GNPs are dispersed in isopropyl alcohol without the addition of any surfactant and combined with PLA dissolved in chloroform. The GNP-PLA composites exhibit improved mechanical properties (improvement in tensile strength by 44% and maximum strain by 57%) even at a low GNP threshold concentration of 2 wt %. The GNP-PLA composites also exhibit an electrical conductivity of over 1 mS/cm at >1.2 wt %. The GNP-PLA composites can be 3D-printed into various features with electrical conductivity and mechanical flexibility. This work presents a new direction toward advanced 3D printing technology by providing higher flexibility in designing multifunctional 3D printed features.

Publisher Correction: Superplasticity in a lean Fe-Mn-Al steel.

The original PDF version of this Article omitted to state that "Jeongho Han and Seok-Hyeon Kang contributed equally to this work" in the affiliations section. This has now been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.

Superplasticity in a lean Fe-Mn-Al steel.

Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here we introduce a new compositionally lean (Fe-6.6Mn-2.3Al, wt.%) superplastic medium Mn steel that resolves these limitations. The medium Mn steel is characterized by ultrafine grains, low material costs, simple fabrication, i.e., conventional hot and cold rolling, low deformation temperature (ca. 650 °C) and superior ductility above 1300% at 850 °C. We suggest that this ultrafine-grained medium Mn steel may accelerate the commercialization of superplastic ferrous alloys.Research in new alloy compositions and treatments may allow the increased strength of mass-produced, intricately shaped parts. Here authors introduce a superplastic medium manganese steel which has an inexpensive lean chemical composition and which is suited for conventional manufacturing processes.

Design for Fe-high Mn alloy with an improved combination of strength and ductility.

Recently, Fe-Mn twinning-induced plasticity steels with an austenite phase have been the course of great interest due to their excellent combination of tensile strength and ductility, which carbon steels have never been able to attain. Nevertheless, twinning-induced plasticity steels also exhibit a trade-off between strength and ductility, a longstanding dilemma for physical metallurgists, when fabricated based on the two alloy design parameters of stacking fault energy and grain size. Therefore, we investigated the tensile properties of three Fe-Mn austenitic steels with similar stacking fault energy and grain size, but different carbon concentrations. Surprisingly, when carbon concentration increased, both strength and ductility significantly improved. This indicates that the addition of carbon resulted in a proportionality between strength and ductility, instead of a trade-off between those characteristics. This new design parameter, C concentration, should be considered as a design parameter to endow Fe-Mn twinning-induced plasticity steel with a better combination of strength and ductility.