Faraday Cage Research Articles

Designing F/P Hybrid Polymer as Ultrastable Cationic Shielding Interphase for High‐Performance Lithium Metal Batteries

AbstractDendrite growth on electrode‐electrolyte interphase has severely limited applications of lithium metal batteries (LMBs). Here, we developed an ionic alternating polymer with fluorocarbons and phosphonium cations in repeating units to regulate Li deposition for the first time. The combined functionalities in the F/P hybrid polymer exhibit remarkable characteristics as a protective layer on top of Li anode, demonstrating outstanding electrochemical stability, ion flux redistributing capability and adaptive chain mobility. Based on characterizations and simulations, this cationic interlayer could effectively furnish long‐standing electrostatic shielding for anodes, allowing restrained coating decomposition and homogenized electric field distribution to induce dendrite‐free Li deposition, and enabling full cells with enhanced rate and long‐term cycling performance. Given the importance of LMBs, this work will promote polymer design to stabilize anodes with superior electrochemical behavior.

Tangential electrostatic field at metal surfaces

Abstract In electrodynamics, it has been long believed that when the electrostatic equilibrium is reached the electrostatic field outside a metal is always perpendicular to the metal surface. However, the tangential electrostatic field (TEF) may be discovered at the metal surface through the mechanical-electric coupling in the work. The TEF can lead to new knowledge and more accurate modification on electrostatics of metals including the electrostatic equilibrium conditions, uniqueness theorem, method of image charges, electrostatic shielding, Thompson’s theorem, and Green’s reciprocation theorem. The TEF and the mechanical-electric coupling can also indicate that an intrinsically intensive electrostatic field may exist at the nanoparticle surface. Thereby a unified model could be constructed for the surface-enhanced Raman scattering (SERS) which has been a long-standing problem in physics and chemistry in recent several decades. Furthermore, when the micro-electro-mechanical systems (MEMS) work, the deformation of the metal plate can induce an additional electrostatic field and a newly attractive electrostatic force between the metal plates. They may be important for the design and fabrication of high-performance MEMS devices. Overall, the revealed TEF may update the physical knowledge of the electrostatics of metals in electrodynamics and may acquire widespread applications in the areas of SERS, MEMS, and so on.

Phonon Polaritons: A New Paradigm for Light‐Controllable Heat Sources

AbstractPhotothermal applications, such as therapy, imaging, and catalysis, necessitate heat sources capable of generating high temperatures under mid‐infrared (mid‐IR) illumination. However, commonly used metal nanostructures suffer from low efficiency due to their high carrier concentrations, resulting in shallow surface heating and optical range restrictions. To overcome these limitations, this work proposes a novel approach employing materials that support phonon polaritons (PhPs) as a promising paradigm for light‐controllable heat sources. The theoretical demonstration reveals that hexagonal boron nitride (hBN) nanorods can produce up to 46 times more heat compared to plasmonic gold counterparts under resonant monochromatic light. This superior heating capability stems from the unique properties of PhPs, which enable stronger field confinement and deeper penetration within the nanostructure, leading to higher efficiency by circumventing the electrostatic shielding effect associated with plasmonic heating. Furthermore, this work demonstrates that the heating performance of hBN antennas can be optimized by manipulating their size, geometry, and material loss. Notably, the use of isotopically pure hBN can triple the heat power. These findings highlight the tremendous potential of hBN antennas as light‐controllable heat sources, opening up new possibilities for IR photothermal applications by harnessing materials that support PhPs.

FAST Polarization Mapping of the Supernova Remnant VRO 42.05.01

We have obtained the polarization data cube of the supernova remnant (SNR) VRO 42.05.01 at 1240 MHz using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). Three-dimensional Faraday synthesis is applied to the FAST data to derive the Faraday depth spectrum. The peak Faraday depth map shows a large area of enhanced foreground rotation measure (RM) of ∼60 rad m−2 extending along the remnant’s “wing” section, which coincides with a large-scale H i shell at −20 km s−1. The two depolarization patches within the “wing” region with RMs of 97 rad m−2 and 55 rad m−2 coincide with two H i structures in the H i shell. Faraday screen model fitting on the Canadian Galactic Plane Survey 1420 MHz full-scale polarization data reveals a distance of (0.7–0.8)d SNR in front of the SNR with enhanced regular magnetic field there. The highly piled-up magnetic field indicates that the H i shell at −20 km s−1 could originate from an old evolved SNR.

Dual mechanism of electrostatic shielding and iodide redox for self-healing lithium metal anodes

Uncontrollable lithium dendrite growth and interfacial parasitic reaction hinder the development of lithium metal batteries (LMBs). The 15-Crown-5 (15-C-5) has shown potential to inhibit dendrite growth due to a self-healing electrostatic shielding (SHES) mechanism. The strong complexation of 15-C-5 with Li+ induces to generate a Li2O-dominated solid electrolyte interphase (SEI), leading to a dramatic increase in inactive Li and dead Li. Meanwhile, the inhomogeneous SEI causes whisker Li tip deposition, which increases the contact specific surface area between the electrolyte and Li, further intensifies electrolyte consumption. This has impeded the development of 15-C-5 electrolyte. Therefore, we propose to add I3–/I– redox to eliminate the negative effect of 15-C-5, including several advantages: the rescuing engineering of inactive Li and dead Li during deposition process; the promotion of columnar Li tips deposition and the circumvention of electrolyte consumption; enhancing SEI mechanical strength and lowering the Li nucleation barrier. The SHES mechanism occurrs during Li deposition and I3–/I– redox works during Li stripping. Boosted interfacial stability and cycle life can be retained due to the dual mechanism effect of SHES and I3–/I– redox. The work provides a dual-mechanism strategy from optimizing electrolytes to deep the insight into the research toward self-healing lithium metal anodes.

Assessing the Shield Termination Approaches in Aircraft Wiring to Against the Lightning Indirect Effects

Lightning is a natural phenomenon where high voltages and currents suddenly discharge. It can be caused by clouds themselves, clouds between them, or clouds near the earth. Aircraft are also at risk of being struck by lightning and there is currently no way to prevent this from happening. Instead, efforts are being made to protect by reducing the effects of lightning. Metal structures in aircraft form a Faraday cage which helps in preventing lightning currents from entering the aircraft. However, composite structures, which are becoming more prevalent in the aviation sector, are less efficient in doing so compared to metals. Additionally, openings such as windows in the aircraft can break the Faraday cage and allow strong electromagnetic fields to penetrate. Hence, all equipment used on board the aircraft must be adequately qualified and lightning-proof. The most popular technique used to reduce the indirect effects of lightning on electronics is cable shielding. In this study, various shielding termination techniques for their effectiveness against indirect effect of lightning examined and It is found that utilizing a 360˚ backshell termination technique provided to be highly effective, providing protection of nearly 3 dB. The results obtained from the experiments are compared with simulation results and previous studies and it has been observed that the obtained results are consistent with each other.

Investigation of Faraday cage materials with low eddy current and high RF shielding effectiveness for PET/MRI applications

Objective. This study aims to evaluate radiofrequency (RF) shielding effectiveness (SE), gradient-induced eddy current, magnetic resonance (MR) susceptibility, and positron emission tomography (PET) photon attenuation of six shielding materials: copper plate, copper tape, carbon fiber fabric, stainless steel mesh, phosphor bronze mesh, and a spray-on conductive coating. Approach. We evaluated the six shielding materials by implementing them on identical clear plastic enclosures. We measured the RF SE and eddy current in benchtop experiments (outside of the MR environment) and in a 3T MR scanner. The magnetic susceptibility performance was evaluated in the same MR scanner. Additionally, we measured their effects on PET detectors, including global coincidence time resolution, global energy resolution, and coincidence count rate. Main results. The RF SEs for copper plate, copper tape, carbon fiber fabric, stainless steel mesh, phosphor bronze mesh, and conductive coating enclosures were 56.8 ± 5.8, 63.9 ± 4.3, 33.1 ± 11.7, 43.6 ± 4.5, 52.7 ± 4.6, and 47.8 ±7.1 dB, respectively, in the benchtop experiment. Copper plate and copper tape experienced the most eddy current at 10 kHz in the benchtop experiment and also generated the largest ghosting artifacts in the MR scanner. Stainless steel mesh had the highest mean absolute difference (7.6 ±0.2 Hz) compared to the reference in the MR susceptibility evaluation. The carbon fiber fabric and phosphor bronze mesh enclosures caused the largest photon attenuation, reducing the coincidence count rate by 3.3%, while the rest caused less than 2.6%. Significance. The conductive coating proposed in this study is shown to be a high-performance Faraday cage material for PET/MRI applications based on its overall performance in all the experiments conducted in this study, as well as its ease and flexibility of manufacturing. As a result, it will be selected as the Faraday cage material for our second-generation MR-compatible PET insert.

Decorating local Li+ solvation structure and optimizing solid electrolyte interphase with potassium trifluoroacetate for dendrites-free lithium metal anodes

Fabricating a stable and robust solid electrolyte interphase to realize the dendrites-free lithium (Li) deposition morphology in the existing commercial electrolytes remains challenging. Here, the cost-effective potassium trifluoroacetate is proposed as an electrolyte additive, in which TFA− anions have the capability to involve in constructing solid electrolyte interphase with abundant inorganic species by modulating local Li+ solvation structure. It is found that TFSI− and NO3− anions in the electrolyte can be recruited into Li+ primary solvent sheath to replace partial solvent molecules confirmed by classical molecular dynamic simulations. This is due to the strong polar interaction between TFA− anions and Li+, which is favorable for weakening the coordination of solvent molecules proved by density functional theory calculation. Besides, with the assistance of electrostatic shielding of K+, the Li deposition morphology is greatly improved. Benefiting from the potassium trifluoroacetate additive, Li+ transference number (tLi+) of 0.68, considerable ionic conductivity (σLi+) of 8.93 × 10−4 S cm−1, and stable cycling over 400 h at 1.0 mA cm−2 are obtained. Moreover, the full cells coupling with LiFePO4 cathode exhibit a low overpotential of 212.41 mV and high capacity retention of 87.67% after 283 cycles under the current density of 1.0 C.

Colloid Electrolyte with Weakly Solvated Structure and Optimized Electrode/Electrolyte Interface for Zinc Metal Batteries

Aqueous zinc batteries are considered as a viable candidate for cost-effective and environmentally sustainable energy storage technology but are severely hampered by the notorious dendrite growth and parasitic reactions at the zinc anode side. Herein, we propose a bifunctional colloidal electrolyte design that utilizes upconversion nanocrystals, i.e., NaErF4@NaYF4, as a solid additive to provide the sustained release of functional metal and fluoride ions, which can effectively improve the reversibility of the Zn anode to inhibit dendrite growth and hydrogen evolution through forming an electrostatic shielding layer and in situ constructing a ZnF2-enriched protective interface. Experimental characterization and molecular dynamics simulation jointly confirm that the NaErF4@NaYF4 additive could modify the Zn2+ solvation environment in the vicinity of the NaErF4@NaYF4 surface via the strong electrostatic coupling with Zn2+ ions. As a consequence, the modified electrolyte enables stable zinc plating/stripping over 2100 h at a current density of 3 mA cm–2 and a capacity of 1 mAh cm–2 in symmetric cells. The assembled Zn||MnO2 full cells with a modified electrolyte can operate stably for 1600 cycles at 2 A g–1. This work thereby has great potential for the exploration of multifunctional electrolyte additives toward long-lasting aqueous Zn metal batteries.

Bifunctional Dynamic Adaptive Interphase Reconfiguration for Zinc Deposition Modulation and Side Reaction Suppression in Aqueous Zinc Ion Batteries.

Dendrite growth and electrode/electrolyte interface side reactions in aqueous zinc-ion batteries (AZIBs) not only impair the battery lifetime but also pose serious safety concerns for the battery system, hindering its application in large-scale energy storage systems. Herein, by introducing positively charged chlorinated graphene quantum dot (Cl-GQD) additives into the electrolyte, a bifunctional dynamic adaptive interphase is proposed to achieve Zn deposition regulation and side reaction suppression in AZIBs. During the charging process, the positively charged Cl-GQDs are adsorbed onto the Zn surface, acting as an electrostatic shield layer that facilitates smooth Zn deposition. In addition, the relative hydrophobic properties of chlorinated groups also build a hydrophobic protective interface for the Zn anode, mitigating the corrosion of the Zn anode by water molecules. More importantly, the Cl-GQDs are not consumed throughout the cell operation and exhibit a dynamic reconfiguration behavior, which ensures the stability and sustainability of this dynamic adaptive interphase. Consequently, the cells mediated by the dynamic adaptive interphase enable dendrite-free Zn plating/stripping for more than 2000 h. Particularly, even at 45.5% depth of discharge, the modified Zn//LiMn2O4 hybrid cells still retain 86% capacity retention after 100 cycles, confirming the feasibility of this simple approach for application with limited Zn sources.

Modulation of Insulin Amyloid Fibrillization in Imidazolium-Based Ionic Liquids with Hofmeister Series Anions.

Amyloid fibrils have immense potential to become the basis of modern biomaterials. The formation of amyloid fibrils in vitro strongly depends on the solvent properties. Ionic liquids (ILs), alternative solvents with tunable properties, have been shown to modulate amyloid fibrillization. In this work, we studied the impact of five ILs with 1-ethyl-3-methylimidazolium cation [EMIM+] and anions of Hofmeisterseries hydrogen sulfate [HSO4-], acetate [AC-], chloride [Cl-], nitrate [NO3-], and tetrafluoroborate [BF4-] on the kinetics of insulin fibrillization and morphology, and the structure of insulin fibrils when applying fluorescence spectroscopy, AFM and ATR-FTIR spectroscopy. We found that the studied ILs were able to speed up the fibrillization process in an anion- and IL-concentration-dependent manner. At an IL concentration of 100 mM, the efficiency of the anions at promoting insulin amyloid fibrillization followed the reverse Hofmeister series, indicating the direct binding of ions with the protein surface. At a concentration of 25 mM, fibrils with different morphologies were formed, yet with similar secondary structure content. Moreover, no correlation with the Hofmeister ranking was detected for kinetics parameters. IL with the kosmotropic strongly hydrated [HSO4-] anion induced the formation of large amyloid fibril clusters, while the other kosmotropic anion [AC-] along with [Cl-] led to the formation of fibrils with similar needle-like morphologies to those formed in the IL-free solvent. The presence of the ILs with the chaotropic anions [NO3-] and [BF4-] resulted in longer laterally associated fibrils. The effect of the selected ILs was driven by a sensitive balance and interplay between specific protein-ion and ion-water interactions and non-specific long-range electrostatic shielding.

Second-harmonic currents in rf-biased, inductively coupled discharges

Capacitively-coupled plasmas generate strong current or voltage signals at harmonics of their driving frequencies. Inductively coupled plasma (icp) systems generally do not, unless they are equipped with capacitively-coupled rf bias, which generates strong signals at harmonics of its driving frequency. Recently, however, at an asymmetric, rf-biased electrode, a current component was detected at the second harmonic of the inductive source frequency, not the rf-bias frequency. The origin of this current is here investigated (in argon discharges at 1.3 Pa) by comparison with measurements made at a symmetric electrode and predictions made by two numerical models. The first simulates the sheath at the rf-biased electrode; the second models the plasma. Because capacitive coupling from the inductive source was minimized by a Faraday shield, the nonlinearity of the sheath contributes negligible second-harmonic current. Modulation of the photon flux in the plasma, however, produces a second-harmonic current photoemitted from the rf-biased electrode. The external circuitry and nonlinear inductive coupling produce a second-harmonic sheath voltage, which in turn generates second-harmonic current both directly and through a transit-time effect. The second model simulates how electrons emitted from the electrode—and then reflected at the quartz dielectric window of the inductive source—are deflected by the electric and magnetic fields in the plasma. It also gives predictions for the transit-time effect. Magnetic deflections and the transit-time effect usually dominate the electric deflection. Together these three mechanisms produce a second-harmonic current that has a Fourier amplitude approximately half the current that is elastically reflected at the icp window. These results suggest it may be possible to use the second-harmonic current to determine the elastic reflection coefficient at the window.

Molecular mechanisms of pyrophosphate-mediated selective adsorption of Ni(II) by polyamine-grafted chitosan–wood flour composite from alkaline plating wastewater: EXAFS investigation and theoretical calculations

The efficient removal of complexed heavy metals (HMs) from alkaline electroless plating wastewater is still challenging. A polyamine-grafted chitosan–wood flour-based composite (ACS-AWF) was optimally synthesized. Its adsorption behavior toward Ni(II) in simulated pyrophosphate (PP, the main complextant)–Ni plating wastewater and underlying mechanisms were examined. PP considerably promoted Ni(II) adsorption by up to 108.1%, and the enhancement tolerated excess PP or other substances. Ni(II) adsorption by ACS-AWF was 1.38–∼10 times that of several commercial HM-favored resins in the same complexed system. According to the liquid solute species tracking, solid chemical characterizations (eg. synchrotron radiation X-ray adsorption spectroscopy), and theoretical calculations, it was found that Ni(II), primarily as NiP2O72−, could be captured by charge-assistant coordination with the surface polyamine. Then, the coadsorption of PP altered the interface properties via both electrostatic shielding and bridging effect, enhancing Ni(II)–amine coordination efficiency. A dinuclear multilayer coordination structure [-amine–Ni–PP–Ni–amine-] was proposed as the dominant Ni(II) binding mode in the presence of PP. Ni(II) and PP could be sequentially desorbed from ACS-AWF using gradient elution with ＞95.5% Ni(II) purity. ACS-AWF was then stably reused in five cycles (capacity loss ＜10%). These results may guide adsorbent design and application in HM purification and recycling from complexed wastewater.

Hybrid methods of radiation shielding against deep-space radiation

In the last decade, NASA and other space exploration organizations have focused on making crewed missions to different locations in our solar system a priority. To ensure the crew members’ safety in a harsh radiation environment outside the protection of the geomagnetic field and atmosphere, a robust radiation protection system needs to be in place. Passive shielding methods, which use mass shielding, are insufficient as a standalone means of radiation protection for long-term deep-space missions. Active shielding methods, which use electromagnetic fields to deflect charged particles, have the potential to be a solution that can be used along with passive shielding to make deep-space travel safer and more feasible. Past active shielding studies have demonstrated that substantial technological advances are required for active shielding to be a reality. However, active shielding has shown potential for near-future implementation when used to protect against solar energetic particles, which are less penetrating than galactic cosmic rays (GCRs). This study uses a novel approach to investigate the impacts of passive and active shielding for protection against extreme solar particle events (SPEs) and free-space GCR spectra under solar minimum and solar maximum conditions. Hybrid shielding configuration performance is assessed in terms of effective dose and radiobiological effectiveness (RBE)-weighted dose reduction. A novel electrostatic shielding configuration consisting of multiple charged planes and charged rods was chosen as the base active shielding configuration. After a rigorous optimization process, two hybrid shielding configurations were chosen based on their ability to reduce RBE-weighted dose and effective dose. For protection against the extreme SPE, a hybrid active-passive shielding configuration was chosen, where active shielding was placed outside of passive shielding. In the case of GCRs, to gain additional reduction compared to passive shielding, the passive shielding configuration was placed before the active shielding to intentionally fragment HZE ions to improve shielding performance.

Ordered self-assembly of DNA-modified nanoparticles in salt solutions

DNA-modified nanoparticles (DNA-NPs) have been widely applied in medical diagnosis and biosensors. Molecular dynamics (MD) simulation, a common method to track the dynamic changes of ions, nanoparticles and DNA, is able to predict the assembly behavior of DNA-NP, thus providing a fast and efficient method for precise regulation of experiments. At present, the simulation research of the DNA-NP self-assembly mainly focuses on DNA bonding, while the effects of electrostatic interactions between DNA and DNA, ions and ions, ions and DNA on the self-assembly structure and mechanism have not been systematically studied. We have constructed a coarse-grained model of DNA-NP self-assembly in salt solutions to appropriately simulate the experimental conditions. It can well match the directionality and saturation of DNA base pairing, as well as the electrostatic repulsive interactions between DNA, and ion-related effects. How the distribution of ions, electrostatic shielding and DNA hybridization regulate the assembled structure and kinetic properties of DNA-NP in monovalent or divalent salt solutions with different ionic concentrations are deeply investigated. Our simulated results reveal the thermodynamic stability and reversibility of the ordered self-assembly of DNA-NPs, in accordance with experimental results. They also provide a reasonable explanation for the susceptibility of nanoparticles to aggregation at high salt concentration for multivalent salt environments. Our research gives a preliminary attempt for the simulation of DNA-NP self-assembly in salt solution, provides theoretical guidance for designing DNA nanomaterials with controllable structures and properties, and promotes its research progress in the fields of medical diagnosis and biosensors.

Cationic, electrostatic shielding, ion-sieving nanocellulose separators stabilize zinc metal anodes

A bio-based, electrostatic shielding, ion-sieving separator is proposed by surface amine functionalization of nanocellulose paper to stabilize Zn metal anode, for the first time. Such cationic nanocellulose separator exhibits uniformly and narrowly distributed nanopores with immobilized cationic groups, which yields a homogenous current distribution at the separator/electrode interfaces, inhibits SO42− migration, enhances the Zn2+ transference number to 0.73, and generates a zincophobic repulsion layer to eliminate the “tip effect”. Unlike pristine nanocellulose separator, the combination of ion-sieving nanofibrous network and immobilized electrostatic shielding functional groups lead to smoother and more compact Zn deposition/stripping behavior during repeated cycles. Hence, highly reversible Zn metal anodes and durable supercapacitors are realized: the symmetric Zn//Zn cells can last 180 h under a high current density of 20 mA cm−2 with a high capacity of 10 mAh cm−2, and the Zn//activated carbon supercapacitor shows a discharge capacity of 104.3 mA g−1 at 1 A g−1 with a capacity retention ratio of ∼ 80% after 2500 cycles. The surface charge engineering approach constitutes a practical separator modification strategy toward even Zn deposition and a promising route for the development of aqueous Zn-based energy storage devices with improved sustainability and enhanced cycling stability.

Spatial Layouts of Low-Entropy Hydration Shells Guide Protein Binding.

Protein-protein binding enables orderly biological self-organization and is therefore considered a miracle of nature. Protein‒protein binding is driven by electrostatic forces, hydrogen bonding, van der Waals force, and hydrophobic interactions. Among these physical forces, only hydrophobic interactions can be considered long-range intermolecular attractions between proteins due to the electrostatic shielding of surrounding water molecules. Low-entropy hydration shells around proteins drive hydrophobic attraction among them that essentially coordinate protein‒protein binding. Here, an innovative method is developed for identifying low-entropy regions of hydration shells of proteins by screening off pseudohydrophilic groups on protein surfaces and revealing that large low-entropy regions of the hydration shells typically cover the binding sites of individual proteins. According to an analysis of determined protein complex structures, shape matching between a large low-entropy hydration shell region of a protein and that of its partner at the binding sites is revealed as a universal law. Protein‒protein binding is thus found to be mainly guided by hydrophobic collapse between the shape-matched low-entropy hydration shells that is verified by bioinformatics analyses of hundreds of structures of protein complexes, which cover four test systems. A simple algorithm is proposed to accurately predict protein binding sites.

Research on the shielding effect of the electrode frames in the electrostatic precipitator

ABSTRACT The electrostatic precipitator (ESP) plays an important role in the dust removal from the flue gas. Currently, the shielding effect of electrode frames seriously affects the electric field distribution and dust removal efficiency of ESPs. In order to explore the shielding effect and propose an improved measurement, an experimental setup with RS barbed electrodes and a 480 C type dust collector electrode plate was built to evaluate the corona discharge characteristics. The current density distribution on the surface of the collecting plate was tested on an ESP experimental setup. The effect of electrode frames on the current density distribution was also systematically investigated. The test results show that the current density distribution on the position that directly opposites the needle of RS corona discharge is much higher, on the contrary, the current density on the position that directly opposites the frames is almost zero. It indicates that the frames have a shielding effect on the corona discharge. Therefore, the dust collection efficiency is low in actual ESPs due to the dust escape route caused by the shielding effect. To solve the problem, a new ESP with a split-level frame arrangement was proposed. Implications: The conventional electrostatic precipitators are often affected by the electrostatic shielding effect, which leads to uneven charging. The particulate removal efficiency decreases and escape channels are very easy to form. In this study, effective measures were proposed to solve the electrostatic shielding of dust collector frames by studying their electrostatic shielding mechanism. The study provides theoretical support for the improvement of electrostatic precipitators, while improving the dust removal efficiency.

3D printed cartridge for high-speed capillary electrophoresis with sheath liquid thermostatting and contactless conductivity detection

The high-speed capillary electrophoresis (HSCE) method is a technique that utilizes a high electric field strength applied through a short capillary to reduce the time required for sample separation. However, the increased electric field strength may result in pronounced Joule heating effects. To address this, we describe a 3D-printed cartridge with integrated contactless conductivity detection (C4D) head and a sheath liquid channel. The C4D electrodes and Faraday shield layers are fabricated by casting Wood's metal in chambers inside the cartridge. Effective thermostatting of the short capillary is achieved by flowing Fluorinert liquid, which provides better heat dissipation compared to airflow. A HSCE device is created by using the cartridge and a modified slotted-vial array sample-introduction approach. Analytes are introduced through electrokinetic injection. With the help of sheath liquid thermostatting, background electrolyte concentration can be increased to several hundred mM, resulting in improved sample stacking and peak resolutions. Additionally, the baseline signal is flattened. Typical cations such as NH4+, K+, Na+, Mg2+, Li+, and Ca2+ can be separated within 22 s with an applied field strength of 1200 V/cm. The limit of detection ranges from 2.5 to 4.6 μM with a relative standard deviation of migration times of 1.1–1.2% (n = 17). The method has been applied to detect cations in drinking water and black tea leaching for drink safety testing, and to identify explosive anions in paper swabs. Samples can be directly injected without the need for dilution.

Preparation of high internal phase Pickering emulsion by centrifugation for 3D printing and astaxanthin delivery

Oil in water high internal phase Pickering emulsion (HIPEs) stabilized by edible colloid particles have attracted considerable attention for three-dimensional (3D) printing and delivery of a hydrophobic bioactive. In this paper, a facile route for preparing oil in water HIPEs was demonstrated, only requiring centrifuging gliadin/gelatinized starch nanocomposites (G/SNPs) stabilized pre-emulsions. The surface properties of G/SNPs were engineered which helped prevent oil coalescence during centrifugation, while obtaining HIPEs with oil phase fractions up to 77.3%, simultaneously. The resultant HIPEs exhibited shear-thinning behavior with high solid viscoelasticity. Furthermore, HIPEs with internal phase fraction above 80% were successfully prepared simply by adjusting the ionic strength. The HIPEs with suitable rheology properties for 3D printing were obtained, and the enhanced viscoelasticity and thixotropic recovery could be attributed to the electrostatic shielding under higher ionic strength. In addition, the light stability and bioaccessibility of astaxanthin were significantly improved by HIPEs, and more than 90% astaxanthin was retained after heating at 95 °C for 30 min. These results proved a new route for producing HIPEs with improved performance, opening new possibilities for manufacturing future food and delivery of hydrophobic bioactive molecules.