Electrostatic Powder Coating as a Novel Process for High‐Voltage Insulation Applications

Advanced Materials Interfaces

Nanostructured materials that mimic structural coloration in nature can be synthetically created by colloidal self‐assembly. To maximize optical effects, the natural world integrates melanin as a broadband absorber to remove incoherently scattered light. Polydopamine (PDA) is used as a synthetic analog of natural melanin to systematically investigate the influence of absorber quantity and distribution on color saturation in colloidal photonic crystals. The absorbing PDA is integrated into two distinct ways: homogenous colloidal crystals are produced from core–shell particles with incrementally increasing polydopamine shells, and heterogeneous colloidal crystals are formed by co‐assembly of varying ratios of polystyrene (PS) and absorbing PS@PDA particles. The chromaticity is quantified by converting the measured spectra to reconstructed colors in the L*a*b* color sphere to identify structures with optimal color …

Langmuir

Unraveling the two-dimensional (2D) structural ordering of colloidal particles assembled at a flat surface is essential for understanding and optimizing their physical properties. So far, grazing-incidence small-angle X-ray scattering (GISAXS) has been widely used to determine crystallographic information on 2D self-assembled structures of nanosize objects. However, solving the structure of 2D lattices consisting of micrometer (μm)-sized objects still remains a challenge using scattering methods. Here, a model 2D SCALMS (supported catalytically active liquid metal solution) template is fabricated from μm-sized polystyrene (PS) spheres that form a monolayer on top of the flat solid support. GISAXS patterns of the sample were collected for rotation angles around its surface normal in steps of 3°. For every rotation angle, different Bragg-type interference maxima along the out-of-plane (qz) direction were observed. On …

Microfluidics and Nanofluidics

In this study, we show the design and manufacturing of microfluidic deterministic lateral displacement (DLD) devices for sub-micrometer particle separation. For that purpose, devices with pillar gaps of 4 µm and a periodicity of 50 were designed. After photolithographic manufacturing of SU-8 masters with different heights (15 and 30 µm) and vertical sidewalls for soft-lithographic replication with polydimethylsiloxane (PDMS) the influence of flow rate on the separation efficiency of 0.45 and 0.97 µm particles was investigated. The 15 µm devices were operated at 0.125 and 0.5 µl/min sample flow rate and the 30 µm devices at 0.5 and 2.0 µl/min, respectively. Excellent separation efficiencies were observed for both device heights at the lower sample flow rates, while separation efficiencies decreased at the respective higher sample flow rates. The decrease in separation efficiency was attributed to deformation of the soft …

Advanced Materials

Continuous gradients in self-assembled materials can provide functionality exceeding that of the homogenous case. In article number 2208745, Markus Retsch and co-workers present a synthesis method that provides gradient size distributions via a controlled extraction emulsion process (CrEEP). The high degree of control allows the fabrication of a continuous-gradient photonic glass with enhanced broadband reflectance.

ACS photonics

Molecular chirality plays fundamental roles in biology. The chiral response of a molecule occurs at a specific spectral position, determined by its molecular structure. This fingerprint can be transferred to other spectral regions via the interaction with localized surface plasmon resonances of gold nanoparticles. Here, we demonstrate that molecular chirality transfer occurs also for plasmonic lattice modes, providing a very effective and tunable means to control chirality. We use colloidal self-assembly to fabricate non-close packed, periodic arrays of achiral gold nanoparticles, which are embedded in a polymer film containing chiral molecules. In the presence of the chiral molecules, the surface lattice resonances (SLRs) become optically active, i.e., showing handedness-dependent excitation. Numerical simulations with varying lattice parameters show circular dichroism peaks shifting along with the spectral positions of …

Advanced Engineering Materials

A novel strategy for manufacturing of the main insulation of high‐voltage rotating machines is presented. The developed process is based on established electrostatic powder coating equipment. Using complete automation enables the precise and reproducible application of homogeneous powder coating layers. Individual layers can be stacked by process repetitions to achieve a desired layer thickness. This coating strategy alters the particle deposition process by introducing additional capillary bridges that significantly increase powder adhesion. A systematic parameter study is performed to provide process–structure relations connecting various process parameters with the resultant coating thickness and homogeneity. The parameters of the developed coating process are iteratively improved to maximize coating homogeneity and minimize defect density, the most critical parameters in high‐voltage insulation …

Macromolecular Materials and Engineering

Liquid‐infused surfaces exhibit remarkable repellency properties toward water, oils, and complex fluids and are widely applied to maintain clean, operational, and high‐performing surfaces in various fields, from the biomedical sector to marine infrastructure. Polydopamine (PDA) forms an ideal base layer for the development of such coatings as it adheres to virtually any substrate and can be chemically modified via amino‐containing molecules to adjust the surface properties. Here, strategies are explored to increase the mechanical stability of such coatings by i) incorporating imidazole during film formation to increase crosslinking, and ii) formation of a composite consisting of the organic PDA and an inorganic siliceous porous coating by infiltration of a preformed porous silica layer with PDA. Both strategies exhibit improved resistance to tangential shear assessed by a sandpaper abrasion test and to dynamic …

Advanced Materials

2D colloidal crystallization provides a simple strategy to produce defined nanostructure arrays over macroscopic areas. Regularity and long‐range order of such crystals is essential to ensure functionality, but difficult to achieve in self‐assembling systems. Here, a simple loudspeaker setup for the acoustic crystallization of 2D colloidal crystals (ACDC) of polystyrene, microgels, and core–shell particles at liquid interfaces is introduced. This setup anneals an interfacial colloidal monolayer and affords an increase in average grain size by almost two orders of magnitude. The order is characterized via the structural color of the colloidal crystal, the acoustic annealing process is optimized via the frequency and the amplitude of the applied sound wave, and its efficiency is rationalized via the surface coverage‐dependent interactions within the interfacial colloidal monolayer. Computer simulations show that multiple …

Advanced Materials

Colloidal crystals and glasses manipulate light propagation depending on their chemical composition, particle morphology, and mesoscopic structure. This light–matter interaction has been intensely investigated, but a knowledge gap remains for mesostructures comprising a continuous property gradient of the constituting particles. Here, a general synthetic approach to bottom‐up fabrication of continuous size gradient colloidal ensembles is introduced. First, the technique synthesizes a dispersion with a specifically designed gradual particle size distribution. Second, self‐assembly of this dispersion yields a photonic colloidal glass with a continuous size gradient from top to bottom. Local and bulk characterization methods are used to highlight the significant potential of this mesostructure, resulting in vivid structural colors along, and in superior light scattering across the gradient. The process describes a general …

Langmuir

Colloidal lithography utilizes self-assembled particle monolayers as lithographic masks to fabricate arrays of nanostructures by combination of directed evaporation and etching steps. This process provides complex nanostructures over macroscopic areas in a simple, convenient, and parallel fashion without requiring clean-room infrastructure and specialized equipment. The appeal of the method comes at the price of imperfections impairing the optical quality, especially for arrayed nanostructures relying on well-ordered lattices. Imperfections are often generically mentioned to rationalize the discrepancy between experimental and simulated resonances. Yet, little attention is given to detailed structure–property relationships connecting typical defects directly with the optical properties. Here, we use a correlative approach to connect nano- and microscopic defects occurring from the colloidal lithography process with …

Nature communications

Bifurcations in kinetic pathways decide the evolution of a system. An example is crystallization, in which the thermodynamically stable polymorph may not form due to kinetic hindrance. Here, we use confined self-assembly to investigate the interplay of thermodynamics and kinetics in the crystallization pathways of finite clusters. We report the observation of decahedral clusters from colloidal particles in emulsion droplets and show that these decahedral clusters can be thermodynamically stable, just like icosahedral clusters. Our hard sphere simulations reveal how the development of the early nucleus shape passes through a bifurcation that decides the cluster symmetry. A geometric argument explains why decahedral clusters are kinetically hindered and why icosahedral clusters can be dominant even if they are not in the thermodynamic ground state.

Communications Physics

The narrow escape theory (NET) predicts the escape time distribution of Brownian particles confined to a domain with reflecting borders except for one small window. Applications include molecular activation events in cell biology and biophysics. Specifically, the mean first passage time can be analytically calculated from the size of the domain, the escape window, and the diffusion coefficient of the particles. In this study, we systematically tested the NET in a disc by variation of the escape opening. Our model system consisted of micro-patterned lipid bilayers. For the measurement of , we imaged diffusing fluorescently-labeled lipids using single-molecule fluorescence microscopy. We overcame the lifetime limitation of fluorescent probes by re-scaling the measured time with the fraction of escaped particles. Experiments were complemented by matching stochastic numerical simulations. To conclude, we confirmed the …

Journal of Rheology

Interfacial rheology is important for understanding properties such as Pickering emulsion or foam stability. Currently, the response is measured using a probe directly attached to the interface. This can both disturb the interface and is coupled to flow in the bulk phase, limiting its sensitivity. We have developed a contactless interfacial method to perform interfacial shear rheology on liquid/liquid interfaces with no tool attached directly to the interface. This is achieved by shearing one of the liquid phases and measuring the interfacial response via confocal microscopy. Using this method, we have measured steady shear material parameters such as interfacial elastic moduli for interfaces with solidlike behavior and interfacial viscosities for fluidlike interfaces. The accuracy of this method has been verified relative to a double-wall ring geometry. Moreover, using our contactless method, we are able to measure lower …

Catalysis Science & Technology

Supported catalytically active liquid metal solution (SCALMS) materials represent a recently developed class of heterogeneous catalysts, where the catalytic reaction takes place at the highly dynamic interface of supported liquid alloys. Ga nuggets were dispersed into nano-droplets in propan-2-ol using ultrasonication followed by the addition of Pt in a galvanic displacement reaction – either directly into the Ga/propan-2-ol dispersion (in situ) or consecutively onto the supported Ga droplets (ex situ). The in situ galvanic displacement reaction between Ga and Pt was studied in three different reaction media, namely propan-2-ol, water, and 20 vol% water containing propan-2-ol. TEM investigations reveal that the Ga–Pt reaction in propan-2-ol resulted in the formation of Pt aggregates on top of Ga nano-droplets. In the water/propan-2-ol mixture, the desired incorporation of Pt into the Ga matrix was achieved. The ex situ …

Langmuir

Colloidal crystals are excellent model systems to study self-assembly and structural coloration because their periodicities coincide with the wavelength range of visible light. Different assembly methods inherently introduce characteristic defects and irregularities, even with nearly monodisperse colloidal particles. Here, we investigate how these imperfections influence the structural coloration by comparing two techniques to obtain colloidal crystals. 3D colloidal crystals produced by convective assembly are well-ordered and periodically arranged but show microscopic cracks. (2+1)D colloidal crystals fabricated by stacking individual monolayers show a decreased hexagonal order and limited crystal registration between single monolayers in the z-direction. We investigate the optical properties of both systems by comparing identical numbers of layers using correlative microspectroscopy. These measurements show …

The present invention relates to a process for producing a particle dispersion comprising the steps of: a) providing a dispersion consisting of a solvent and solid core particles, b) providing a solution of a soluble, interfacially-active polymer having a molecular weight of more than 5 kDa, c) mixing said dispersion of solid core particles with said polymer solution, d) removing free polymer from the obtained mixture; wherein in step a) the solvent is selected from an organic solvent, a mixture of at least two organic solvents or a mixture of at least one organic solvent with water; wherein in step c), the amount of the soluble, interfacially-active polymer mixed with said dispersion of solid core particles exceeds the amount of polymer required to coat the surface of each of the solid core particles with a monolayer of the polymer; wherein step d) is repeated until the requirement described by the following formula is fulfilled:

Microfluidics and Nanofluidics

Polydimethylsiloxane (PDMS) is a popular material to rapidly manufacture microfluidic deterministic lateral displacement (DLD) devices for particle separation. However, manufacturing and operation challenges are encountered with decreasing device dimensions required to separate submicron particles. The smaller dimensions, notably, cause high hydraulic resistance, resulting in significant pressure even at relatively low throughputs. This high pressure can lead to PDMS deformation, which, in turn, influences the device performance. These effects may often be overlooked in the design and operation of devices but provide a systematic source of error and inaccuracies. This study focuses in detail on these effects and investigates pillar deformation in detail. Subsequently, we discuss a potential solution to this deformation using thermal annealing to stiffen the PDMS. We evaluate the influence of stiffness on the …

Self-organisation is the spontaneous emergence of spatio-temporal structures and patterns from the interaction of smaller individual units. Examples are found across many scales in very different systems and scientific disciplines, from physics, materials science and robotics to biology, geophysics and astronomy. Recent research has highlighted how self-organisation can be both mediated and controlled by confinement. Confinement is an action over a system that limits its units’ translational and rotational degrees of freedom, thus also influencing the system's phase space probability density; it can function as either a catalyst or inhibitor of self-organisation. Confinement can then become a means to actively steer the emergence or suppression of collective phenomena in space and time. Here, to provide a common framework and perspective for future research, we examine the role of confinement in the self …

Materials Horizons

Nanostructuration is a promising tool for enhancing the performance of sensors based on electrochemical transduction. Nanostructured materials allow for increasing the surface area of the electrode and improving the limit of detection (LOD). In this regard, inverse opals possess ideal features to be used as substrates for developing sensors, thanks to their homogeneous, interconnected pore structure and the possibility to functionalize their surface. However, overcoming the insulating nature of conventional silica inverse opals fabricated via sol–gel processes is a key challenge for their application as electrode materials. In this work, colloidal assembly, atomic layer deposition and selective surface functionalization are combined to design conductive inverse opals as an electrode material for novel glucose sensing platforms. An insulating inverse opal scaffold is coated with uniform layers of conducting aluminum …

Advanced Engineering Materials

Embroidered Property Materials (EPMs) represent a paradigm shift in materials engineering, offering a novel approach to conventional material modifications. Through a precise “embroidering” of properties in precise locations, EPMs optimize existing substrates without the need for additional or removal layers. This technique, realized through the activation of targeted chemical and physical phenomena, enables the local alteration of the microstructure in response to controlled external stimuli, exemplifying the deliberate design of material zones with predefined properties. Demonstrating this concept, bulk and confined laser treatment was precisely applied to standard carbon steel (C45), resulting in localized martensitic transformation. This localized microstructural change manifests in a significantly altered deformation behaviour when contrasted with untreated areas, emphasizing the potent capabilities of EPMs …

Advanced Engineering Materials

This study aims to characterize the mechanical response of thick Al whiskers under tension. Wire‐shaped whiskers are fabricated by stress‐induced migration using an original sample structure. Straight and single‐crystal whiskers are suspended between a W probe tip attached to a micromanipulator and an atomic force microscope tip attached to a nanostage using electron beam irradiation hardening glue. Tensile tests are conducted by pulling the probe tip. A tensile strength of 1 GPa is obtained for a whisker with a diameter of 500 nm. Observations using a high‐voltage electron microscope show that the whisker is deformed by pencil‐shaped sharp necking with signs of recrystallization at the tip, which displays a novel mechanical response of Al whiskers. The obtained tensile strength is more than twice that of whiskers with similar diameters reported in the literature, indicating that the tensile strength of not …

Advanced Engineering Materials

Metal swarf has the advantage of being eco‐friendly due to their ability to be recycled and reused, in addition to being lightweight, energy‐absorbing, and cost‐effective. For practical applications in various industrial fields, effective and accurate modeling for each case should be developed in consideration of its physical properties. This study investigates the mechanical behavior of aluminum chip compaction employing a new computational simulation approach based on a pressure‐dependent porous continuum model. Two material parameters of densification rate (n) and the ratio of shear modulus (m) are proposed and adjusted for different swarf. The numerical results show good agreement with the experimentally obtained axial stress—relative density relation of three various samples, demonstrating a close relationship between the parameters n and the chip geometry. This study can be applied for further …

Advanced Engineering Materials

In the present work, transition metal‐containing preceramic silicon polymers were synthesized via chemical modification of a commercially available organopolysilazane with Hf and Ta amido complexes as well as with borane dimethyl sulfide complex. The incorporation of transition metals into the polymer structure, their influence on ceramization and processability were thoroughly investigated. Moreover, the prepared preceramics were coated onto silicon wafers via spin coating and converted into crack‐free, amorphous SiHfTa(B)CN‐based ceramic coatings with excellent adhesion to the substrate. The composition of the ceramic coatings was investigated via X‐ray photoelectron spectroscopy (XPS) and their high‐temperature behavior was studied via oxidation tests performed at 1100 °C. Moreover, a thermal cycling procedure to temperatures above 1250 °C with rapid heating and cooling rates (i.e., in the …

Advanced Engineering Materials

Coextrusion by robocasting is a suitable process for fabricating multimaterial ceramic structures. Herein, the robocasting process is used to fabricate core–shell structures, combined with subsequent liquid silicon infiltration (LSI). Thus, reaction‐bonded silicon carbide (RBSC), reaction‐bonded boron carbide (RBBC), and reaction‐bonded silicon–boron carbide composites are produced. The LSI process offers the possibility to circumvent high temperatures and pressures used in traditional fabrication. Pastes with high solid loading and necessary carbon content are used in order to combine the robocasting with the subsequent LSI process. The influence of the paste rheology on the sample fabrication of multimaterial core–shell structures of reaction‐bonded carbides is investigated. The key rheological data, such as the viscosities of the combined pastes, are correlated with the observations from the microstructural …

Advanced Engineering Materials

Silver nanowire (AgNW) emerges as a next‐generation transparent electrode material, offering enhanced flexibility and ease of fabrication compared to traditional transparent electrode materials, such as metallic oxides. In the previous research, the uniform deposition of AgNWs on flat surfaces is demonstrated, exhibiting high conductivity, flexibility, and excellent transmittance. However, the evolution of nano‐electronics technology necessitates the fabrication of transparent electrodes on non‐flat surfaces, such as those found in zenithal bistable devices and reconfigurable Fresnel lenses. In this study, a method is proposed to deposit AgNW material on uneven surfaces using the Mylar‐bar‐coating method, with a polyvinyl chloride (PVC)‐based Fresnel lens serving as the target surface. Additionally, the impact of varying AgNW suspension concentrations on transmittance and sheet resistance is investigated. To …

Advanced Engineering Materials

The field of soft robotics is rapidly progressing toward applications including; wearable electronics, prosthetics, and biomedical devices. This is leading to demand for flexible, embedded high‐performance strain sensors to deliver real‐time feedback on the static configurations and dynamic motions of these robotic devices, to ultimately enable the levels of autonomous control and structural monitoring required for intelligent manipulation. Herein, aerosol jet printing (AJP) technology is utilized to generate arbitrary piezoresistive strain sensor layouts on fibrous paper suitable for direct integration into elastomeric soft robots. A custom graphene nanoplatelet ink with a viscosity of around 2.70 cP has been formulated for optimized atomization and patterning of conductive traces via AJP. Single and multilayer printing onto different paper substrates are explored; with the nominal resistance of the printed tracks varying …

Advanced Engineering Materials

This study demonstrates the mechanical, self-sensing, and biological characteristics of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)-engineered 3D-printed polyetheretherketone (PEEK) composite scaffolds, utilizing custom-made feedstocks. Microstructural analysis and macroscale testing reveal that the PEEK/CNT scaffolds with 6 wt% CNT content and 46% relative density achieve a gauge factor of up to 75, a modulus of 0.64 GPa, and a compressive strength of 64 MPa. The PEEK/CNT2.5/GNP2.5 scaffolds evince still better performance, at a relative density of 73%, reporting a modulus of up to 1.1 GPa and a compressive strength of 122 MPa. Importantly, stability in mechanical and piezoresistive performance up to 500 cycles is noted, indicating a durable and reliable performance under cyclic loading. Murine preosteoblast cells (MC3T3-E1) are used to biologically characterize sulfonated scaffolds over 14 days. Cytotoxicity, DNA, and alkaline phosphatase (ALP) levels are quantified through in vitro assays, evaluating cell viability, proliferation, and osteogenic properties. Notably, PEEK/CNT 6 wt% scaffolds exhibit nearly 80% cytocompatibility, while PEEK/CNT2.5/GNP2.5 scaffolds reach nearly 100%. Both types of scaffolds support cell differentiation, as evidenced by elevated ALP levels. These findings carry significant promise in bone tissue engineering, paving the way for the development of adaptive, intelligent structural implants boasting enhanced biocompatibility and self-sensing capabilities.

Advanced Engineering Materials

Triboelectric nanogenerators (TENGs) are becoming attractive devices for harvesting mechanical energy. 3D printing (3DP) is a newly reported technique for the development of this device. This technique is not fully explored for the fabrication of triboelectric materials and compatible printing processes. Herein, three main 3DP techniques including powder‐based multijet fusion, resin‐based polyjet fusion, and filament‐based fused deposition modeling are utilized to investigate new sets of 3DP triboelectric materials. Mechanical to electrical conversion efficiency of 3D printed and commercially available negative and positive triboelectric materials are compared and investigated. Polyamide ‐12 (PA12), Veroclear, acrylonitrile‐styrene‐acrylate (ASA), copper‐coated polylactic acid (Cu‐PLA), polycarbonate (PC), and polyethylene terephthalate glycol (PETG) are fabricated using compatible 3D printing techniques. 3D …

Advanced Engineering Materials

This study investigates the impact of exposure to aggressive environments, specifically saline conditions per ASTM B117 standard, on the shear strength of adhesive‐bonded joints, crucial for ensuring structural integrity in various industrial applications like automotive, aerospace, and construction. Employing an epoxy‐based adhesive to bond AISI304 steel, specimens undergo 14‐ and 28‐day salt spray treatments to simulate harsh working conditions. Torsional shear strength assessment of steel‐to‐steel adhesive joints is conducted using a torsion test methodology, with an analytical approach used to extrapolate adhesive joint shear strength. This research contributes to understanding adhesively bonded joint performance in challenging environmental conditions, and how the shear strength of the bonded joints changes in relatively small amount of time, offering valuable insights for robust structural designs …

Advanced Engineering Materials

This study demonstrates the mechanical, self‐sensing, and biological characteristics of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)‐engineered 3D‐printed polyetheretherketone (PEEK) composite scaffolds, utilizing custom‐made feedstocks. Microstructural analysis and macroscale testing reveal that the PEEK/CNT scaffolds with 6 wt% CNT content and 46% relative density achieve a gauge factor of up to 75, a modulus of 0.64 GPa, and a compressive strength of 64 MPa. The PEEK/CNT2.5/GNP2.5 scaffolds evince still better performance, at a relative density of 73%, reporting a modulus of up to 1.1 GPa and a compressive strength of 122 MPa. Importantly, stability in mechanical and piezoresistive performance up to 500 cycles is noted, indicating a durable and reliable performance under cyclic loading. Murine preosteoblast cells (MC3T3‐E1) are used to biologically characterize …

Advanced Engineering Materials

The rheological behavior and deformation mechanisms of a new powder metallurgy (P/M) superalloy at various deformation conditions are researched. The deformation conditions have significant influence on the rheological stress. Increasing the deformation temperature or decreasing the strain rate can decrease the rheological stress. The discontinuous hardening and softening phenomena are observed at the strain rate of 1 s−1, resulting from the complex phase transformation and dynamic recrystallization. Besides, the deformation activity energy (Q) declines with increasing the strain. The phenomenon is attributed to the spheroidization of γ′ phase and the decreased content/aspect ratio of γ′ phase. The deformation mechanisms of the researched superalloy are the accumulation of dislocation, stacking faults shearing, dislocations pinned by γ′ phase, and the formation of microtwins during hot deformation …

Advanced Engineering Materials

The tensile loading history of continuous carbon fiber composites is classified using machine learning (ML) and crystallographic data from the polymer matrix. Composites with polyamide‐4,10 matrix and unidirectional 10° and 45°, and 0°/90° cross‐ply layups are subjected to single‐cycle uniaxial tensile loads corresponding to 25–90% of their nominal maximum strain, and mapped by X‐ray diffraction with approximately 1000 data points from each layup. The unit cell alterations are used as a feature set for optimizing three ML algorithms; linear discriminant analysis, support vector machines (SVM), and gradient‐boosted decision trees (GBDT), with the objective of predicting five discrete loading magnitudes of the respective layups. It is demonstrated that SVMs and GBDTs can be trained to achieve a classification accuracy of >90% on unseen test data, both in cases where the feature set consists of data points from …

Advanced Engineering Materials

To improve the efficiency and lifetime of mechanical components, new lubrication systems are needed. Two complementary material classes, which have demonstrated a promising tribological performance, are ionic liquids and MXenes (2D transition metal carbides and nitrides). Herein, Ti3C2Tx MXenes are used as additives in ionic liquids (ILs) to improve their load‐carrying capacity under boundary lubrication. The specifically synthesized ILs share the same cation (trioctyl(methyl)phosphonium) but different anions (dimethyl phosphate and dibutyl phosphate for IL1 and IL2, respectively) to assess the effect of the anion's alkyl chain length. The wear reduction performance is tested with a cylinder‐on‐ring contact in a standardized Brugger tester, which is suitable to study boundary lubrication and to assess the antiwear ability of the IL/MXene lubricant blends. MXenes indicate an excellent dispersibility in both ILs …

Advanced Engineering Materials

This study demonstrates the mechanical, self‐sensing, and biological characteristics of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)‐engineered 3D‐printed polyetheretherketone (PEEK) composite scaffolds, utilizing custom‐made feedstocks. Microstructural analysis and macroscale testing reveal that the PEEK/CNT scaffolds with 6 wt% CNT content and 46% relative density achieve a gauge factor of up to 75, a modulus of 0.64 GPa, and a compressive strength of 64 MPa. The PEEK/CNT2.5/GNP2.5 scaffolds evince still better performance, at a relative density of 73%, reporting a modulus of up to 1.1 GPa and a compressive strength of 122 MPa. Importantly, stability in mechanical and piezoresistive performance up to 500 cycles is noted, indicating a durable and reliable performance under cyclic loading. Murine preosteoblast cells (MC3T3‐E1) are used to biologically characterize …

Advanced Engineering Materials

The carrier transport and the exciton recombination region, which are strongly affected by temperature, are essential to organic light‐emitting diodes (OLEDs) under thermal stress. We selected different charge carrier transport materials with different glass transition temperature (Tg) to investigate their effect on the thermal stability of OLEDs. By calculating the carrier mobility at different annealing temperatures and comparing the simulated values by the Arrhenius equation, the effect of the thermal stress on the performance of OLEDs was analyzed. Then, using the luminescent dye as a probe adjacent to the emitting layer and charge transporting layer to identify the exciton recombination region at different temperatures and driving voltages, it was revealed that replacing the functional material with low Tg with a high‐Tg one could effectively increase the thermal stability of the device to 100°C. The optimized devices …

Advanced Engineering Materials

Employing 3D printing bone scaffolds with various polymers is growing due to their biocompatibility, biodegradability, and good mechanical properties. However, their biological properties need modification to have fewer difficulties in clinical experiments. Herein, the fused‐deposition modeling technique is used to design triply‐periodic‐minimal‐surfaces polylactic‐acid scaffolds and evaluate their biological response under static and dynamic cell culture conditions. To enhance the biological response of 3D‐printed bone scaffolds, graphene‐oxide (GO) is coated on the surface of the scaffolds. Fourier‐transform infrared spectroscopy, X‐ray diffraction, and energy‐dispersion X‐ray analysis are conducted to check the GO presence and its effects. Also, computational fluid dynamics analysis is implemented to investigate the shear stress on the scaffold, which is a critical parameter for cell proliferation under dynamic …

Advanced Engineering Materials

The electrical conductivity (EC), mechanical strength, hot tearing susceptibility (HTS), and related microstructure of Al–xNi–0.55Mg–0.55Si conductor alloys (x = 1–4 wt%) are investigated. Adding Mg and Si into Al–Ni‐based alloys, numerous β″/β′ precipitate after T5 and T6 treatments, thus significantly improving the EC and mechanical strength. The HTS of the alloys reduces significantly as the Ni content increases, mainly because of an increase in the eutectic Al–Al3Ni and a reduction in the grain size. Under T5 condition, the tensile strengths increase gradually with the Ni content and reach a medium strength level, with yield strength (YS) of 158–205 MPa and EC of 47.1–50.7% IACS. After applying T6, all alloys achieve a high strength, with YS of 246–287 MPa and EC of 47.7–51.1% IACS. However, the strength decreases with increasing Ni content. In general, the Al3Ni–0.55Mg–0.55Si alloy presents a …

Advanced Engineering Materials

While inkjet printing on many hydrophilic surfaces can be achieved through control of drop spacing and droplet deposition delay alone, the same for hydrophobic substrates prove to be challenging. The low surface energies of hydrophobic surfaces lead to dewetting, unwanted coalescence of wet drops, and bulging, preventing intact and uniform lines of low‐viscosity ink to form. In this paper, we have adapted the stacked coin strategy, a well‐established and successful technique for hydrophilic surfaces, for use on hydrophobic surfaces. Stacked coin morphology occurs when the time taken to deposit a subsequent overlapping droplet in a pattern is longer than the evaporation time of the prior droplet. On hydrophobic surfaces, it is considerably more challenging and the parameter window for successful printing is smaller than on hydrophilic surfaces, thus requiring in‐depth study to implement this methodology on …

Advanced Engineering Materials

The arising of novel paradigms in human–computer interaction, including tangible user interfaces, shape‐changing interfaces, or ubiquitous computing, is breaking down the boundary between physical and digital realms, leading to more natural and immersive forms of interaction. Advances in active and responsive smart materials allow to transform once inanimate objects, such as books, into actively responsive objects. Herein, a hybrid interactive book has been developed. It includes a capacitive touchpad, a piezoelectric speaker, and a piezoresistive platform for drawing and writing digitalization. All interactive elements are based on electroactive polymer films and are processed by additive manufacturing techniques. This work provides a compelling demonstration of how advanced materials can be seamlessly integrated in traditional physical interfaces to enhance interactivity and user experience.