To solve the poor cyclability of faradic supercapacitors (SCs), the authors reported a unique porous carbon (PC) coating with “gap shell” structure on carbon fiber cloth (CFC)/NiS2 materials. This gap shell PC coating was fabricated by combining atomic layer deposition (ALD) Al2O3 and molecular layer deposition alucone, followed by carbonization and etching. The as-prepared CFC/NiS2/PC composites were directly used as binder-free electrodes for SCs. Benefited from its novel nanostructure, the CFC/NiS2/PC electrode shows a large specific capacitance of 1034.6 F/g at 1 A/g and considerable rate capability of 67% capacitance, retaining ratio within 1–20 A/g. The cyclability of the CFC/NiS2/PC electrode is enhanced by 50% relative to the mere CFC/NiS2 after 2000 cycles, which is attributed to the gap and electrically conductive PC coating. Hence, this work provides a promising approach to design gap shell layer for improved cyclability of faradic SCs and other practical applications in energy storage electronics.

This study compared the effect of gelatin- and chitosan-based scaffolds on osteoblast biomineralization. These scaffolds have been modified using methacrylate and laponite nanosilicates to improve their mechanical strength and support osteoblast function. Scaffold materials were prepared to have the same compressive strength (14–15 MPa) such that differences in cell response would be isolated to differences in biopolymer chemistry. The materials were tested for rheological properties to optimize the bio-ink for successful 3D printing using a robocast-assisted deposition system. Osteoblasts were cultured on the surface of 3D-printed methacrylated chitosan-laponite (MAC-Lp), methacrylated gelatin-laponite (MAG-Lp), MAC, and MAG scaffolds. MAC-Lp scaffolds showed increased cell viability, cell growth, and biomineral formation as compared to MAG-Lp scaffolds. FTIR results showed the presence of higher biomineral phosphate and extracellular matrix (ECM) collagen-like amide formation on MAC-Lp scaffolds as compared to MAG-Lp scaffolds. MAC-Lp scaffolds showed increased density of ECM-like tissue from SEM analysis, stained mineral nodules from Alizarin staining, and the existence of Ca–P species evident by X-ray absorbance near edge structure analysis. In conclusion, MAC-Lp scaffolds enhanced osteoblast growth and biomineral formation as compared to MAG-Lp scaffolds.

The present work investigates the influence of sodium doping on structural, morphological, photoluminescence, linear, nonlinear (NL), and optical limiting (OL) parameters of NaxCd1−xS thin films (where x= 0.0, 0.5, 1.0, 2.5, and 5.0 wt%) deposited on glass substrates using spray pyrolysis route. X-ray diffraction and Raman analyses confirmed the hexagonal polycrystalline nature of films. Crystallite sizes were decreased from 30 to 17 nm with doping. Scanning electron microscopy (SEM) micrographs also confirmed the nanocrystalline spherical growth. Energy dispersive X-ray spectroscopy (EDS) and SEM mapping studies revealed the presence and homogeneous distribution of individual elements. Transmission of films is found to lie between 45 and 60%. Although the low doping caused the reduction of the effective band gap, higher doping caused a blue shift in band gap, with an associated reduction in crystallite sizes. The refractive index values are found within 1–2 in visible and their maximum values (in range 2.65–3.16) are observed at 2500 nm. Photoluminescence (PL) spectra showed broad emission peak at ∼520 ± 10 nm. Dielectric and NL analyses were also carried out. OL results were promising for the systematic gradual decrease of intensity from 100 to 72%, with doping for power regulating applications.

BaxSr(1−x)TiO3 (BST) thin films were fabricated on a Ti substrate using micro-arc oxidation (MAO) in an aqueous solution with the addition of 0.6 M Ba(OH)2, 0.4 M Sr(OH)2, and 0.05 M EDTA. The morphology, composition, and electrical properties of BST films prepared under different processing times were characterized, and MAO growth characteristics of BST films were discussed. Results indicate that dielectric and ferroelectric properties of BST films are positively correlated with surface morphology dependent on MAO spark patterns. To obtain a smooth and compact film, the large spark stage should be avoided. During MAO processes, elements from the substrate and electrolyte solution migrate in opposite directions under an electric field, resulting in Ba, Sr, Ti, and O elements exhibiting a gradient distribution between the BST film and the Ti substrate. BST film prepared using MAO is composed of two layers: an outer loose layer and an inner dense layer. In addition, because of the position of discharge breakdown continually changing, the interface between the film and the substrate is uneven. As MAO processing time increases, BST film thickness increases and ferroelectric property improves. When processing time is 15 min, the residual polarization intensity (2Pr) of the BST film is about 4.9 μC/cm2.

A novel g-C3N4 nanoparticle@porous g-C3N4 (CNNP@PCN) composite has been successfully fabricated by loading g-C3N4 nanoparticles on the porous g-C3N4 matrix via a simply electrostatic self-assembly method. The composition, morphological structure, optical property, and photocatalytic performance of the composite were evaluated by various measurements, including XRD, SEM, TEM, Zeta potential, DRS, PL, FTIR, and XPS. The results prove that the nanolization of g-C3N4 leads to an apparent blueshift of the absorption edge, and the energy band gap is increased from 2.84 eV of porous g-C3N4 to 3.40 eV of g-C3N4 nanoparticle (Fig. 6). Moreover, the valence band position of the g-C3N4 nanoparticle is about 0.7 eV lower than that of porous g-C3N4. Therefore, the photo-generated holes and electrons in porous g-C3N4 can transfer to the conduction band of g-C3N4 nanoparticle, thereby obtaining higher separation efficiency of photo-generated carriers as well as longer carrier lifetime. Under visible-light irradiation, 6CNNP@PCN exhibits the highest photocatalytic performance (Fig. 8) on MB, which is approximately 3.4 times as that of bulk g-C3N4.

A CoNiCrAlTaHfY/Co composite coating was prepared on the etched C/C composites by using duplex vapor phase surface alloying treatments, i.e., Co alloying and Co–Ni–Cr–Al–Ta–Hf–Y alloying. Microstructures and oxidation behavior of the coated C/C composites were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The result showed that the CoNiCrAlTaHfY/Co composite coating, 25 μm in thickness, was compact and composed of CrCoTa, AlCo2Ta, AlxCry, AlxNiy, and Co. The coating adhesion can be enhanced by microwave plasma chemical vapor deposition etching of matrix surface and adding a Co intermediate layer between the CoNiCrAlTaHfY top layer and C/C composites substrate. The honeycomb structure after etching was helpful to alloying element absorb and diffuse into substrate surface, and the composite coating continuation was improved by the Co buffer layer. After exposing in air for 180 min at 1000 °C, the bulk C/C composites volatilized while the loss rate of coated C/C composites was 0.82%, showing an improved oxidation resistance. Mixed oxides mainly containing Al2O3 and Cr2O3 were formed in the composite coating surface and protected the C/C composites from oxidation in air.

Poly(phthalaldehyde) (pPHA) and copolymers with aliphatic aldehydes were investigated as dry-develop, positive-tone photoresist. Exposure of the films loaded with a photoacid generator to 248 nm radiation creates an acid that depolymerizes the polymer into volatile monomers, allowing the development of features by vaporization rather than solution-based processes. By controlling the acid content, the vaporization rate of the reaction products, and the degree of liquid formation of the decomposed polymer, control of spatial resolution and the quality of polyaldehyde dry-develop photoresist was achieved. Heat, vacuum, and forced convection were evaluated as development techniques in determining the resist sensitivity, contrast, and resolution. Forced convection of heated nitrogen was the most controllable development method for pPHA films. Five-micron lines and spaces were printed. Poly(aldehyde) copolymer resins had slightly lower spatial resolution but were able to be developed faster due to higher vapor pressure of the depolymerized monomers. Cold photo-exposures and development were used to prevent detrimental liquid formation of the decomposed copolymers. In addition to exploring new dry-development methods that have not been tested before, these findings offer insights into designing better material systems and optimizing processes for dry-develop photoresists.

Polyglycolide (PGA) materials have been widely used in the medical field, but the degradation mechanism in the natural environment is still unclear. High-viscosity PGA was prepared by using twin-screw reaction extrusion polymerization. The mass and intrinsic viscosity of PGA samples, the pH of the solution surrounding the PGA samples in water, and the number of degradation products resulting from the degradation of the PGA samples were studied under different conditions and at different temperatures. PGA does not degrade at 70 °C in either dry air or in a vacuum. Infrared spectroscopy (FTIR) and differential spectroscopy revealed that the PGA samples in water at 70 °C for 40 days had a substantially reduced mass and substantially altered thermal behavior when compared with the control sample (undegraded PGA sample). The degradation of the PGA samples in humid conditions at 70 °C was similar to the degradation of the samples in water at 70 °C. The results of this study indicate that water and water vapor (moisture) in the natural environment are the main causes of PGA degradation, and higher temperatures accelerate the degradation process, which shortens the shelf life and life of PGA.

Air plasma sprayed thermal barrier coatings (TBCs) are used extensively throughout the gas turbine industry for both power and propulsion. As these engines push to higher temperatures, concern for failure from the melt infiltration of ingested siliceous debris [commonly called calcium–magnesium–alumino-silicate (CMAS)] arises, especially in aeroengines. 7 wt% yttria-stabilized zirconia is particularly prone to melt infiltration and stiffening-induced premature failure. Novel TBC materials such as gadolinium zirconate have been introduced for their infiltration-inhibiting CMAS reactions. Past academic work has utilized ideal laboratory furnace environments to study these phenomena. In this work, the influence of TBC microstructure and chemistry on impinging molten CMAS injected via a burner rig is studied. An observational study of the impacted surfaces and location-specific cross-sectional analysis is reported. Results point toward the critical role of surface microstructure on the mobility and reactivity of the molten CMAS.

The safe and efficient capture of radioactive iodine is highly necessary, but still remains an ongoing challenge. Herein, because of its special layer structure, CuBi–CO3-layered double hydroxides (CuBi–CO3-LDHs) are used to serve as a generic platform, and 3D hierarchical flowerlike ZIF-67/CuBi–CO3-LDH composites are synthesized by a simple coprecipitation method. After immobilization, the flowerlike morphology of CuBi–CO3-LDHs can be completely preserved and proved by scanning electron microscope. Various affecting factors on adsorption performance are investigated, including adsorbent dose, initial concentration of iodine, and temperature. The experimental and modeling results manifest that iodine adsorption is accurately elucidated by pseudo-second-order model, and the equilibrium isotherm is accordant with the Freundlich model. Moreover, the regeneration experiment indicates that ZIF-67/CuBi–CO3-LDH composites possess good stability and reusability for the removal of iodine. The possible adsorption mechanisms of iodine on ZIF-67/CuBi–CO3-LDHs involve particular layer structure and the strong interaction between nitrogen of imidazole ring and iodine, which were investigated by X-ray diffraction, energy-dispersive X-ray, and X-ray photoelectron spectroscopy spectra. The good performance for the iodine adsorption indicates that ZIF-67/CuBi–CO3-LDHs may be identified as a promising adsorbent in the field of iodine capture.

Effective cancer therapy is usually limited by the off target distribution of chemotherapeutic drugs and multidrug resistance (MDR) of cancer cells. As a result, the development of a drug delivery system (DDS) capable of targeting cancer cells while at the same time delivering two or more chemotherapeutic drugs is believed to be a good solution to this dilemma. Herein, a hyaluronan-coated meta-organic framework nanoparticles (HM) were fabricated as a DDS in our study to deliver cisplatin (PDD) and oleanolic acid (Ola). Positive results were obtained in our study which reveal that the DDS (HM/PDD/Ola) is favorable in colorectal cancer (HCT116) therapy by enhancing targeted apoptosis and reversing MDR. Compared with applying free drugs or mono DDS, the dual loaded HM/PDD/Ola showed synergistic effects and better performance, which might be a future alternative for the chemotherapy of colorectal cancer.

Biomagnetic field sensors based on AlN/FeCoSiB magnetoelectric (ME) composites desire a resonant frequency that can be precisely tuned to match the biomagnetic signal of interest. A tunable mechanical resonant frequency is achieved when ME composites are integrated onto shape memory alloy (SMA) thin films. Here, high-quality c-axis growth of AlN is obtained on (111) Pt seed layers on both amorphous and crystallized TiNiCu SMA thin films on Si substrates. These composites show large piezoelectric coefficients as high as d33,f= 6.4 pm/V ± 0.2 pm/V. Annealing the AlN/Pt/Ta/amorphous TiNiCu/Si composites to 700 °C to crystallize TiNiCu promoted interdiffusion of Ti into the Ta/Pt layers, leading to an enhanced conductivity in AlN. Depositing AlN onto already crystalline TiNiCu films with low surface roughness resulted in the best piezoelectric films and hence is found to be a more desirable processing route for ME composite applications.

Poly 4-mercaptophenyl methacrylate-carbon nano-onions ((PMPMA-CNOs = f-CNOs) were reinforced with polycaprolactone (PCL) to produce PCL/f-CNO nanocomposites using probe sonication. The physicochemical properties of nanocomposites were systematically studied to analyze cell viability and proliferation. In vitro cytotoxicity of PCL/f-CNO nanocomposites was measured with osteoblast cells, and improved cell viability was observed. The cytotoxicity of f-CNOs to osteoblasts was dose-dependent, and PCL/f-CNO (0.5 wt%) nanocomposites showed more than 90% of viability as compared to pristine PCL. Similarly, PCL/f-CNO (0.5 wt%) nanocomposites showed substantial enhancement in mechanical properties. The yield strength, tensile strength, Young modulus, elastic modulus, and fracture toughness were also upgraded at high content of f-CNOs (0.5 wt%). The concentration of f-CNOs considerably influenced the strengthening of PCL/f-CNO nanocomposites, which shows its degree of colloidal dispersion stability and extent of polymer wrapping within the PCL matrix. Nevertheless, these nontoxic PCL/f-CNO nanocomposites can be used as promising biomaterials for orthopedic applications.

Na–Se batteries are promising energy storage systems for grid and transportation applications, due to the high volumetric energy density and relatively low cost. However, the development of Na–Se batteries has been hindered by the shuttle effect originating from polyselenide dissolution from the Se cathode. Herein, we reported the utilization of nanoscale Al2O3 surface coating by atomic layer deposition (ALD) to protect a microporous carbon/Se (MPC/Se) cathode and reduce polyselenide dissolution. Compared with the pristine MPC/Se, Al2O3-coated MPC/Se cathode exhibited improved discharge capacity, cycling stability, and rate capability in Na–Se batteries. Post-cycling analysis disclosed that Al2O3 coating on MPC/Se cathode effectively suppressed the polyselenide dissolution, facilitated the formation of thin and stable solid electrolyte interphase (SEI) layers, and reduced charge transfer resistance, thus improving the overall performance of Na–Se batteries. This work suggests the effectiveness of interface control by ALD in enabling high-performance Na–Se batteries and might shed light on the development of new-generation Li/Na/K-chalcogenide batteries.

In this study, the effect of the cooling rate on the thermal and thermomechanical behavior of NiTiHf high-temperature shape memory alloy was studied by differential scanning calorimetry and via running isobaric thermal cycling experiments. The cooling rates were set to 5, 10, and 15 °C/min for each cycle in both experiments, while the heating rate was kept as 10 °C/min. It was found that the transformation temperatures and thermal hysteresis values do not depend on the change in the cooling rate. On the other hand, the austenite to martensite transformation enthalpy as measured from DSC analyses increases with the increase in the cooling rate due to the higher measurement sensitivity at higher scanning rates. Recoverable strain values which were determined from isobaric thermal cycling experiments do not differ since the transforming volume does not change with the change of the cooling rate. All these findings are explained based on the fundamental thermodynamical approach.

The computational tool integrating empirical tight binding and full configuration interaction method is utilized to study the structural and optical properties of spherical PbX (X = S, Se, and Te) nanocrystals under various diameters. The nanocrystal architecture plays an essential role in the control of the structural and optical properties. The appearance of the quantum confinement is caused by the reduction of the optical band gaps with the increasing diameters. By changing the chalcogenide types and diameters, the band gaps are modified, with their wavelengths from 380 to 2500 nm, technologically applying for the visible and near-infrared optical devices. The tight-binding band gaps agree well with previously published theoretical and experimental values. The atomistic electron–hole interactions are mainly influenced by the diameters and chalcogenide types. Using the Stokes shift and fine structure splitting, PbS nanocrystal with the immense size may be implemented as a source of entangled photon pairs and optical filter. Finally, the theoretical study reveals the distinctive properties of PbX (X = S, Se, and Te) nanocrystals by changing their architecture for applications in optoelectronic devices and microscopy.

In order to expand the family and improve the bioactivity of oral implant ceramics, the phase structures, mechanical and wetting properties of the hot-pressed yttria-zirconia/multilayer graphene oxide composite (3Y-ZrO2/GO) ceramics were investigated. GO was uniformly distributed in 3Y-ZrO2 powders, forming the C–O–Zr bond during the sintering process. In comparison to raw 3Y-ZrO2 ceramics, the flexural strength and fracture toughness improved up to 200% (1489.96 ± 35.71 MPa) in ZG3 (with 0.15 wt% GO) and 40.9% (8.95 ± 0.59 MPa m1/2) in ZG2 (with 0.1 wt% GO), respectively, while the relative density and Vickers hardness increased slightly. The toughening mechanisms included crack deflection, crack bridging, and GO put-out. Meanwhile, the composite ceramics were transformed into a more hydrophilic direction and indicated a good wetting property. In consideration of mechanical and wetting properties, the ZG3 would be a favorable alternative to the yttria-zirconia ceramic (Y-TZP) in dental implant applications. The results are expected to serve as a technical guidance for the fabrication and evaluation of dental implants.

A novel approach is utilized to investigate the deformation mechanisms at the microstructural level in 3D-printed alloys. The complex formation methods leave a unique and complicated microstructure in the as-built 3D-printed alloys. The microstructure is three leveled, composed of meltpools, grains, and cells. Deformation mechanisms in this microstructure are still highly unexplored due to the complexities of analysis at this scale. To understand these, we establish an image processing framework that converts scanning electron microscope (SEM) images directly into models that are scaled up and 3D printed with representative stiff and soft materials for the proposed material types within the body. These bodies are loaded in uniaxial tension with digital image correlation to study the strain gradient and stress delocalization as a result of the microstructure. The same models were tested through Finite Element Analysis (FEA) with materials similar to reality. Our testing shows the hierarchical material distribution leads to an increased damage tolerance.

Novel three-dimensional (3D) hierarchical macro- to nano-porous titanium (Ti) and TiMo alloys with sufficient compressive strength (CS) were prepared using NaCl spacer and dealloying methods. The dealloying process was implemented by the heat treatment of TiCu and TiMoCu master alloys in Mg powders. The 3D-hierarchical porous structures were composed of large pores having a mean size of 400 μm with interconnected micro-pores in the size of 10–30 μm, where the pore walls possessed numerous nano-pores with a size range of 10–50 nm. The CS and elastic modulus values were 72.4 MPa and 2.67 GPa as well as 92.62 MPa and 3.36 GPa for Ti and TiMo, respectively. The hierarchical porous structure is beneficial for the fast nucleation of bone-like apatite after immersion in simulated body fluid (SBF). In addition, TiMo samples after NaOH and heat treatments provide better apatite formation after soaking in SBF for a week, in comparison with the samples without treatment.

Additive manufacturing (AM) has made long strides in the recent past and rapidly evolved into a promising alternative in specific applications. The aircraft industry is not an exception to this. The true just-intime production possibility is critical for the aircraft maintenance industries, though the lack of material freedom is a major hurdle. Several fire-retardant materials were investigated for AM in the aerospace context, but mainly for fused deposition modeling (FDM). The material consolidation constraints in FDM led to the expansion to the use of selective laser sintering (SLS) to some extent. Nevertheless, the material options are still limited, proprietary, and lack scientific insights into the material consolidation mechanics. Attempts are made in this paper to fill this gap, evaluating a new fire-retardant material for processing by SLS. Experiments conducted to ascertain the material, process, structure, and consolidation relationships indicated energy density levels 0.062–0.070 J/mm2 with laser power 13 W and scan speed varied slightly around 390 mm/s to give the best laser sintering and mechanical property results in polyetherimide powders.