ACS Applied Engineering Materials最新文献

Organic electrochromic polymers hold great potential for integration into low-power flexible electrochromic displays (F-ECDs) due to their wide range of colors and simple processing. However, challenges such as inefficient charge transfer and degradation upon device integration hinder their practical applications. Herein, we report an innovative, general approach that utilizes template-induced supramolecular nanostructuring to engineer established electrochromic polymers, enhancing their performance and durability. We modified a well-known, albeit underperforming in F-ECDs, poly-thiophene polymer (ECP Orange; PT) by incorporating a pyrene appendage, resulting in a copolymer (PTPy) capable of undergoing large-scale assembly in the presence of multi-walled carbon nanotubes (MWCNTs), driven by the establishment of π-π interactions between the pyrene and the MWCNTs (PTPy/MWCNTs). F-ECDs based on these hybrids, produced by spray coating, exhibit improved color switching speeds (t ₉₀ ^OX = 3.6 s, t ₉₀ ^RED = 0.3 s) compared to those of the PT polymer (t ₉₀ ^OX = 53.2 s, t ₉₀ ^RED = 2.5 s). Additionally, PTPy/MWCNTs F-ECDs demonstrate longer cyclability (half-life based on ΔE, ΔE _50% = 17.6k cycles) compared to PT (ΔE _50% = 278 cycles), also when blended with MWCNTs (ΔE _50% = 282 cycles). This work highlights the pivotal role of engineered supramolecular nanostructuring in boosting the performance of organic electrochromic materials, making them suitable for F-ECD scalable commercial applications.

Organic electrochromic polymers hold great potential for integration into low-power flexible electrochromic displays (F-ECDs) due to their wide range of colors and simple processing. However, challenges such as inefficient charge transfer and degradation upon device integration hinder their practical applications. Herein, we report an innovative, general approach that utilizes template-induced supramolecular nanostructuring to engineer established electrochromic polymers, enhancing their performance and durability. We modified a well-known, albeit underperforming in F-ECDs, poly-thiophene polymer (ECP Orange; PT) by incorporating a pyrene appendage, resulting in a copolymer (PTPy) capable of undergoing large-scale assembly in the presence of multi-walled carbon nanotubes (MWCNTs), driven by the establishment of π–π interactions between the pyrene and the MWCNTs (PTPy/MWCNTs). F-ECDs based on these hybrids, produced by spray coating, exhibit improved color switching speeds (t₉₀^OX = 3.6 s, t₉₀^RED = 0.3 s) compared to those of the PT polymer (t₉₀^OX = 53.2 s, t₉₀^RED = 2.5 s). Additionally, PTPy/MWCNTs F-ECDs demonstrate longer cyclability (half-life based on ΔE, ΔE_50% = 17.6k cycles) compared to PT (ΔE_50% = 278 cycles), also when blended with MWCNTs (ΔE_50% = 282 cycles). This work highlights the pivotal role of engineered supramolecular nanostructuring in boosting the performance of organic electrochromic materials, making them suitable for F-ECD scalable commercial applications.

Zwitterionic polymers have proven to be a promising nonfouling material that can be applied in the design of selective layers of thin film composite (TFC) membranes. Extending the permeability and usage of TFC membranes have attracted increasing interest in membrane-based desalination processes since water-flux reduction associated with biofouling nowadays persists as a common challenge. By virtue of its strong hydration, this polymer category is very useful to counteract biofouling in marine and biomedical systems, but the benefits from their application in membrane technology are still emerging. The efficacy of the nonfouling property as a function of the polymer’s molecular weight remains unknown. In pursuit of that vision, this study fosters new scientific insights via probing different molecular weights of poly(carboxybetain methacrylate) (PCBMA) coated on the surface as a selective layer for the prepared TFC membranes. The coated zwitterionic membranes (zM) exhibited excellent performance in preventing water flux decay in a bench-scale forward osmosis system. The prepared zM membranes revealed enhanced hydrophilic properties and retained their operational water flux when compared to the control. Our results suggest that using an intermediate-size molecular weight (PCBMA M_n 50,000) will result in the best operational performance. The intermediate size resulted in the lowest flux decline rate (R_t) of 0.01 ± 0.001 (zM-50) when compared to the unmodified control membrane 0.56 ± 0.071 (M0) after using a model BSA foulant solution. Furthermore, all coated membranes exhibited similar trends in the observed reverse salt flux profiles, as well. The constructed zM membranes will serve as a model to develop further selective layers in the construction of TFC membranes.

Since the development of Ti_2.08Zr null matrix alloy by Sidhu et al. in 1956, only a handful of new null matrix alloys have been reported over the past 70 years. Most of them are not suitable to be utilized in applications due to the poor chemical/physical stabilities and the presence of strong short-range ordering in the structures. For the first time, a new family of V-based null matrix alloys V_1–xM_x (M = Al, Nb, Ta, Ni, Fe, Sn, and Mo; x < 0.1 in molar ratio) were synthesized by an arc melting method. The structural and physical properties were systematically evaluated. All of the alloys crystallize into a cubic body center structure with a space group of Im3̅m. Based on the neutron diffraction (ND), X-ray diffraction, and X-ray pair distribution function, the dopants (except Mo) and V atoms were atomically homogeneous and distributed into the 2a sites of Im3̅m. Small angle neutron scattering was used to probe the bulk neutron transparent properties and the possibilities of dopant clustering at the mesoscopic level. These conditions yield a specific feature in which the ND patterns of the alloys have no diffraction peaks. Hard X-ray absorption spectroscopy revealed that the valence states of V remained 0 in all investigated alloys. Nonetheless, a small degree of charge redistribution were observed. The Coulombic energies of configurations of supercells with different degrees of dopants clustering were also computed for comparison. Tensile tests were also conducted to evaluate the mechanical stress and strain properties. The high-temperature oxidation properties were examined by thermogravimetric analysis differential scanning calorimetry. Among the investigated samples, Nb-doped and Ni-doped V-based alloys show superior chemical and mechanical properties, which could be promising to be utilized to develop advanced in situ devices and high-temperature/pressure neutron scattering sample holders for ND and total scattering measurements.

Hydride content in perovskite oxyhydrides represents a crucial parameter that governs properties of the materials. However, the synthesis of the oxyhidrides with precise control over the hydride content x remains a challenging task because of the time-consuming and/or destructive analytical methods typically used for the determination of x. Here, we report an image-based machine learning (ML) system for prediction of the hydride contents x in a perovskite oxyhydride BaTiO_3–xH_x using a picture of powder material as a quick evaluation method of hydride content x. The ML system, which employs the ExtraTrees algorithm, enabled the prediction of x with a mean absolute error of 0.013 and a low running cost. Although a similar ML system constructed by convolutional neural networks (CNN) that we used in the previous study demonstrated comparable accuracy in the prediction, the system with ExtraTrees was more computationally efficient, thus was applied as a nondestructive and quick analytical method for hydride content x. Using the ML system, detailed profiles of thermal hydrogen release of BaTiO_3–xH_x were quantitatively analyzed to demonstrate the feasibility of fine-tuning the hydride content within 0 ≤ x ≤ 0.4 by adjusting the processing temperature. In the case of powder samples comprising mixtures of the oxyhydride with different hydride contents, the ML-based prediction provided an almost averaged value for x. The present results demonstrate an application of image-based ML for the fine-tuning of oxyhidride materials.

The spontaneous extraction of organic immiscible liquids using oil-repellent membranes holds substantial research significance, particularly in the domain of oil–water mixture separation. However, the development of such membranes is inherently challenging due to the traditionally complex and multistep fabrication processes. This work introduces a single-step hydrothermal approach to engineer a surface with exceptional underwater–oil-repellent properties. Through a hydrothermal reaction, nanoneedles are deposited onto porous hydrophobic nickel foam, imparting it with superhydrophilicity in air and underwater superoleophobicity. The resultant membrane demonstrates gravity-driven separation of immiscible organic liquid mixtures, achieving an impressive separation efficiency of up to 99.6% and an extraordinary flux of 33,839 L m^–2 h^–1. The nanoneedles exhibit negligible oil droplet adhesion and an exceptionally low underwater–oil sliding angle. The unique low oil adhesion properties of the membrane permit seamless underwater manipulation and the transport of immiscible organic microdroplets without any loss. Utilizing its antioil adhesiveness, the membrane facilitates oil transportation in a drop-to-drop configuration, showcasing its potential for sophisticated applications in oil-based microreactors. Furthermore, the membrane exhibits admirable reusability, chemical and thermal stability, and robust resistance to salinity and temperature fluctuations. The simplified fabrication process offers a promising method for producing oil-repellent membranes with profound implications for applications in diverse and demanding underwater environments. Potential applications include oil spill remediation, underwater–oil transport, precise reagent transfer, and the development of droplet-based reactors.

Hydrogen is attractive as a clean fuel as it can be produced directly from water and electricity (electrochemical hydrogen evolution reaction, one of the half-cell reactions in water electrolyzers) and creates the same products (water and electricity) when utilized in a fuel cell. Electrocatalysts are often used to accelerate the kinetics of these reactions, which led to a bloom in the field of electrocatalyst research to search for an efficient, stable, and cost-effective material. Hybrid organic–inorganic 2D electrocatalysts are presented in the current studies, which were prepared by combining two different class of 2D-layered materials: poly(benzoquinone-pyrrole) polymer (BQ-Py polymer) as the organic counterpart and MoS₂ as the inorganic counterpart. The hybrid composite catalysts (named BQ-Py-MoS₂_NS_US and BQ-Py-MoS₂_hyd) exhibit efficient HER activities with high durability in both acidic (aqueous 0.5 M H₂SO₄) and simulated seawater (3.5 wt % of aqueous NaCl) solutions. The studies also reveal some kinetic parameters for electrochemical HER, where it is observed that only 100 mV of extra overpotential is required for the hydrothermally formed hybrid composite to achieve 10 mA cm^–2 of current density as compared to the state-of-the-art HER catalyst (40 wt % Pt–C). This opens up an avenue to develop organic–inorganic hybrid composite catalysts for various electrochemical reactions.

Rare earth elements (REEs) are crucial for clean energy technologies but are predominantly purified by solvent extraction using strong acids. This work explores two adsorbents with selective chemistry based on lanmodulin-derived peptides. Two membrane adsorber platforms were synthesized: (1) a poly(vinylbenzyl chloride) membrane with a grafted poly(allyl methacrylate) network and (2) a poly(arylene ether sulfone) membrane with allyl pendant groups. Both membrane adsorbers were functionalized with LanM1 peptides via a thiol–ene click reaction. The morphology, surface chemistry, and adsorption of select trivalent lanthanides (La, Ce, Pr, Nd) were characterized in pH 4–5 solutions, mimicking phosphogypsum waste streams. Results from the adsorption experiments indicate that the lanmodulin peptide sequence maintains its ability to bind when it is immobilized on the surface of polymer fibers for some ions. Despite the different adsorbent designs, the measured capacity of both adsorbents is on the same order of magnitude, which may be explained by differences in the surface area of the fibers.

Preceramic polymers (PCPs) offer advantages in producing ceramics due to their processability and ability to tailor the final chemistry of the produced material. However, challenges such as volumetric shrinkage and mass loss during pyrolysis often result in polymer-derived ceramics containing pores and cracks. PCP-grafted ceramic nanoparticles (PCPGNPs) have been proposed and studied as a route to mitigate the shrinkage issues associated with neat PCPs. Prior studies on PCPGNPs have principally focused on the synthesis and characterization of neat materials. Dispersing PCPGNPs in commercial preceramic polymer is another attractive, but underexplored, route to control the rheological and char yield properties of PCP systems. In this work, a systematic rheological study of commercial PCP (SMP-877) and PCPGNP (silica with poly(1,1-dimethylpropylsilane) corona) mixtures was executed to develop design rules for the processing of such systems. A rheological study demonstrated the effect of increasing particle concentration on network formation with percolation occurring between 50 and 60 wt %. Samples above the percolation threshold exhibited higher viscosities and rapid shear thinning thus demonstrating their direct-write printability. X-ray photon correlation spectroscopy (XPCS) corroborated the rheology and showed two diffusive modes when the material was above percolation. Mixtures of PCPGNPs and SMP-877 had synergistically higher char yields upon thermal treatment and pyrolysis. XPCS and rheological measurements during thermal treatment identified thermal jamming of the polymer grafts as a key factor in improving the char yield. With the insights gained here, we expect these mixed systems to provide attractive feedstocks for polymer-derived ceramics, with proof-of-principal application as feedstocks for direct ink write (DIW) additive manufacturing.