Liquid Core Research Articles

Complex Core-Shell Architectures through Spatially Organized Nano-Assemblies.

Core-shell structures demonstrate superior capability in customizing properties across multiple scales, offering valuable potential in catalysis, medicine, and performance materials. Integrating functional nanoparticles in a spatially controlled manner is particularly appealing for developing sophisticated architectures that support heterogeneous characteristics and tandem reactions. However, creating such complex structures with site-specific features remains challenging due to the dynamic microenvironment during the shell-forming process, which considerably impacts colloidal particle assembly. Here, we describe a method to spatially deploy nanoscale assemblies within microscale structures comprising a dense shell and a liquid core through colloidal surface decoration coupled with emulsion-based synthesis. Exploiting a spectrum of nanoparticles grafted with incrementally varying densities of organic ligands, we reveal that nanofeatures can be selectively sculpted onto the shell exterior, within the shell wall, and on the interior surface. The versatility of this mechanism is validated by systematically arranging nanoparticles with various compositions, shapes, and dimensions. Spatially integrated nanotitania endows the core-shell structures with localized photocatalytic abilities. Additionally, distinctive surface modifications enable the simultaneous yet independent implantation of diverse nanoparticles, yielding intricate architectures with programmable functions. This generalizable approach showcases a synthetic strategy to attain structural complexity and functional sophistication reminiscent of those of biological systems in nature.

Liquid Metal Nanobiohybrids for High-Performance Solar-Driven Methanogenesis via Multi-Interface Engineering.

Nanobiohybrids for solar-driven methanogenesis present a promising solution to the global energy crisis. However, conventional semiconductor-based nanobiohybrids face challenges such as limited tunability and poor biocompatibility, leading to undesirable spontaneous electron and proton transfer that compromise their structural stability and CH4 selectivity. Herein, we introduced eutectic gallium-indium alloys (EGaIn), featuring a self-limiting surface oxide layer surrounding the liquid metal core after sonication, integrated with Methanosarcina barkeri (M. b). The well-designed M. b-EGaIn nanobiohybrids exhibited superior performance, achieving a maximum CH4 yield of 455.64 ± 15.99 μmol g-1, long-term stability across four successive 7-day cycles, and remarkable CH4 selectivity of >99%. These improvements stem from enhanced proton-coupled electron transfer involving hydrogen atoms at the core-shell interface, further facilitated by the elevated expression of hydrogenases at the abiotic-biotic interface. This study provides an insightful concept for nanobiohybrid design through multi-interface engineering, advancing sustainable and scalable CO2-to-biofuel conversion under ambient conditions.

Liquid Metal Nanobiohybrids for High‐Performance Solar‐Driven Methanogenesis via Multi‐Interface Engineering

Nanobiohybrids for solar‐driven methanogenesis present a promising solution to the global energy crisis. However, conventional semiconductor‐based nanobiohybrids face challenges such as limited tunability and poor biocompatibility, leading to undesirable spontaneous electron and proton transfer that compromise their structural stability and CH4 selectivity. Herein, we introduced eutectic gallium–indium alloys (EGaIn), featuring a self‐limiting surface oxide layer surrounding the liquid metal core after sonication, integrated with Methanosarcina barkeri (M. b). The well‐designed M. b–EGaIn nanobiohybrids exhibited superior performance, achieving a maximum CH4 yield of 455.64 ± 15.99 μmol g−1, long‐term stability across four successive 7‐day cycles, and remarkable CH4 selectivity of >99%. These improvements stem from enhanced proton‐coupled electron transfer involving hydrogen atoms at the core–shell interface, further facilitated by the elevated expression of hydrogenases at the abiotic–biotic interface. This study provides an insightful concept for nanobiohybrid design through multi‐interface engineering, advancing sustainable and scalable CO2‐to‐biofuel conversion under ambient conditions.

Self‐healing and in situ real‐time damage detection of stress‐responsive core‐shell microcapsules polymer composites

AbstractSelf‐healing technology based on micro/nano‐encapsulated materials has shown great potential in extending material lifespan, preventing performance degradation, and reducing maintenance costs. In this study, a novel mechanically responsive microcapsule is successfully prepared by in‐situ polymerization, which can be used for self‐healing of polymer composites. The core‐shell microstructure is characterized, and its stability and potential self‐healing ability is verified. The microcapsule is introduced into polymer matrix, and the epoxy fingerprint region at the preseted defect location is monitored in real‐time under stress stimulus using infrared spectroscopy, revealing the process from microcapsules rupture to liquid core materials releasing and self‐healing mechanism. Tensile tests are conducted to explore the effect of microcapsule fillers on the mechanical properties of polymer composites. The optimal microcapsule content is determined based on the comprehensive evaluations of self‐healing performance. The core‐shell microcapsules provide excellent in‐situ real‐time self‐healing capability for composite matrix damage during load‐bearing. The self‐healing under stress stimulus can better guarantee the reliability of polymer composites in service.Highlights A novel stress responsive microcapsule is prepared for polymer self‐healing. Stability and self‐healing ability of core‐shell microcapsule is verified. Preseted defect is in situ real‐time detected to reveal self‐healing mechanism. Effect of microcapsule content on composite mechanical properties is explored. Self‐healing better guarantee the reliability of polymer composites in service.

Axial and radial random lasing in a biopolymer based liquid core ring resonator

Axial and radial random lasing in a biopolymer based liquid core ring resonator

Study on interface characteristics of n-heptane spray in sub/supercritical conditions

ABSTRACT With the increasing temperature and pressure in the cylinder of the diesel engine, the in-cylinder environment gradually exceeded the thermodynamic critical point of hydrocarbon fuel. Compared with subcritical spray, the phase transformation mechanism of supercritical spray is essentially changed. In this paper, the n-heptane fuel sprays in three conditions case 1 (T1 = 400 K P1 = 2 MPa), case 2 (T2 = 600 K P2 = 2 MPa), and case 3 (T3 = 800 K P3 = 6 MPa) were obtained by high-speed digital schlieren method on the test platform of a constant volume combustion bomb. The spray liquid phase, liquid–gas mixed layer, and mixture were divided, and the variation rules of the spray cone angle, the liquid phase length, maximum interface thickness, and liquid–gas mixed layer area were discussed. The results showed that the higher the ambient temperature and pressure, the more severe the fragmentation of the spray. Compared with the subcritical condition, the spray penetration distance in the supercritical condition tended to be flat faster. Compared with 400 K, 2 MPa condition, the spray cone angle was about 33° and 50% larger at 800 K, 6 MPa condition. The liquid core area at 800 K, 6 MPa condition was 60 cm2, reduced by 75% compared with 400 K, 2 MPa condition, resulting in better spray diffusion and mixing with atmospheric gas. The sensitivity analysis of ambient temperature and pressure on spray characteristic parameters shows that temperature has a greater impact on the interface mixing layer area (VIP = 1.23), and pressure has a greater on penetration distance and spray penetration rate (VIP = 1.23). When the environmental conditions exceed the thermodynamic critical point, the area of the liquid–gas mixed layer increases due to the transformation of spray from evaporation to diffusion and the phenomenon of interfacial layer enrichment. In summary, the supercritical condition promotes the mixing of spray and environment and has a positive effect on spray diffusion and atomization.

Understanding the Formation Dynamics and Physical Properties of Nanocapsules Using Charge Detection Mass Spectrometry.

Characterizing the size, structure, and composition of nanoparticles is vital in predicting and understanding their macroscopic properties. In this work, charge detection mass spectrometry (CDMS) was used to analyze nanocapsules (∼10-200 MDa) consisting of a liquid oleic acid core surrounded by a dense silica outer shell. CDMS is an emerging method for nanoparticle analysis that can rapidly measure the mass and charge of thousands of individual nanoparticles. We find that increasing the feed volume of the tetraethylorthosilicate (TEOS) precursor added to form the silica shell of the nanocapsules yielded both higher and broader nanocapsule mass distributions with differentiable densities. A two-dimensional mass versus charge analysis also revealed the formation of two distinct populations of nanocapsules. These two nanocapsule morphologies were also present in transmission electron microscopy (TEM) images and exhibited low-density spherical cores and crescent-shaped cores where the remainder of the core volume was "filled in" by more dense silica. Nanocapsule shell growth kinetics over a ∼48-h synthesis period were also monitored by sampling the reaction mixture at various times, quenching the sampled aliquots, and then characterizing these time-resolved samples by CDMS. The CDMS data reveal three distinct growth phases in nanocapsule formation; rapid initial nucleation, an "inverted" distribution of silica growth, and a final slow growth phase where the rate of mass increase and final nanocapsule masses are dictated by the initial TEOS feed volumes. CDMS-enabled understanding of the diverse nanocapsule sizes, morphologies, and growth dynamics will allow us to better predict nanocapsule properties while reducing the experimental burden in optimizing nanocapsules for real-world applications.

Temperature effect under different parameters in CuInS2/ZnS core/shell quantum dot-doped liquid core optical fiber

Temperature effect under different parameters in CuInS2/ZnS core/shell quantum dot-doped liquid core optical fiber

A Comprehensive Review of Nanostructured Lipid Carriers: Innovations and Applications in Breast Cancer Treatment.

Nanostructured Lipid Carriers (NLCs) represent a promising advancement in the treatment of breast cancer, addressing the significant challenges posed by conventional chemotherapy, such as poor drug solubility, short half-lives, and high toxicity. This review delves into the potential of NLCs to overcome these limitations, highlighting their unique structure comprising a solid and lipid liquid core stabilized by surfactants. By examining diverse lipid blends used in the preparation of NLCs, the article emphasizes their suitability for targeted drug delivery. Various facets of NLC configuration, categorization, composition, and formulation approaches are systematically explored to provide a comprehensive understanding of their attributes. The findings reveal that NLCs possess a high capacity for lipophilic drugs and offer advantages over traditional lipid-based nanocarriers. The review underscores the pivotal role of NLCs in enhancing drug delivery efficiency for breast cancer therapy while minimizing systemic toxicity. Conclusively, this review positions NLCs as a key player in the evolution of drug delivery systems for breast cancer treatment, providing a detailed outlook on their transformative potential and contributing to a nuanced understanding of their significance in advancing the field of breast cancer treatment.

Experimental Investigation of Spray Drying Breakup Regimes of a PVP-VA 64 Solution Using High-Speed Imaging.

Background: Atomization plays a key role in spray drying, a process widely used in the pharmaceutical, chemical, biological, and food and beverage industries. In the pharmaceutical industry, spray drying is particularly important in the preparation of amorphous solid dispersions, which enhance the bioavailability of active pharmaceutical ingredients when mixed with a polymer. Methods: In this study, a 3D-printed adaptation of a commercial spray dryer nozzle (PHARMA-SD® PSD-1, GEA Group AG) was used to investigate the atomization of PVP-VA 64 polymer solutions under varying flow conditions using high-speed diffuse back-illumination. Results: Unlike pure water, the atomization process of the polymer solution was governed by viscous effects rather than surface tension, as indicated by stringing effects in the liquid core and the formation of larger droplets. In addition, the classical Ohnesorge diagram accurately predicted the atomization regime with increasing Reynolds numbers and could be modified to reasonably predict the breakup regime by considering the transitions between regime boundaries. Conclusions: The use of such a modified diagram facilitates the efficient selection of viscous fluid solutions and process parameters to achieve complete spray formation.

Design and application of a liquid metal ball-supported layered double hydroxide core–shell structure as highly efficient catalysts for the oxygen evolution reaction in rechargeable zinc-air batteries

Zinc-air batteries are critical for future energy storage and electric vehicle development due to their high energy density, environmental friendliness, and abundant raw materials. Layered double hydroxides (LDHs) offer excellent electrocatalytic performance in these batteries, but their poor conductivity and structural instability limit widespread use. In this study, we replaced traditional carbon supports with liquid metal (LM) spheres, onto which an LDH-structured ternary hydroxide was loaded, successfully synthesizing an LM@LDH core–shell composite. This material exhibited superior oxygen evolution reaction (OER) catalytic performance, with an overpotential of only 264 mV at 10 mA cm−2, surpassing carbon-based LDH materials. Detailed characterization and density functional theory (DFT) calculations revealed that LM’s excellent conductivity, promotion of transition metal oxidation states, and reduction in the adsorption free energy of rate-determining intermediates contributed to this enhanced performance. In rechargeable zinc-air batteries, LM@LDH demonstrated exceptional performance, achieving a maximum power density of 120.4 mW cm−2 and a specific capacity of 701.1 mA h gZn-1, while maintaining stability over 4500 charge–discharge cycles. LM@LDH shows great potential for energy catalysis and storage, providing new foundations for developing efficient, cost-effective energy materials.

Microfluidic Fabrication of Oleosin-Coated Liposomes as Anticancer Drug Carriers with Enhanced Sustained Drug Release.

Microfluid-derived liposomes (M-Lipo) exhibit great potential as drug and functional substance carriers in pharmaceutical and food science. However, the low liposome membrane stability, attributed to the liquid core, limits their application range. Oleosin, a natural surfactant protein, can improve the stability of the lipid nanoparticle membrane against various environmental stresses, such as heat, drying, and pH change; in addition, it can enable sustained drug release. Here, we proposed the fabrication of oleosin-coated M-Lipo (OM-Lipo) through self-assembly on a microfluidic chip and the evaluation of its anticancer drug (carmustine) delivery efficiency. Nanoparticle characterization revealed that the oleosin coating slightly lowered the membrane potential of M-Lipo and greatly improved their dispersibility. Additionally, the in vitro drug release profile showed that the oleosin coating improved the sustained release of the hydrophobic drug from the phospholipid bilayer in body temperature. Our results suggest that OM-Lipo has sufficient potential in various fields, based on its easy production, excellent stability, and biocompatibility.

A numerical study of internal transport in oxidizing liquid core–shell iron particles

In an effort to improve the understanding of the rate-limiting mechanisms in liquid iron particle combustion, this study investigates the impact of internal transport within a core–shell structure. The two-dimensional axisymmetric transient continuum model as presented in previous publication (Thijs et al., 2023) is extended, such that the boundary layer between the particle and the gas, surface processes at the particle–gas interface, as well as the internal oxide layer within the particle, considering the transport of reactive O and Fe ions, are resolved. Information from the equilibrium phase diagram, which is included as supplementary data, is used to determine oxidation rate of the particle. The study reveals that finite-rate internal transport significantly alters the temperature evolution compared to models assuming infinitely fast transport. At elevated oxygen concentrations, internal transport becomes rate-limiting, restricting the maximum particle temperature. The core–shell assumption leads to a higher local oxidation degree at the particle–gas interface than the average in the particle, reducing the overall oxygen consumption rate. The maximum particle temperature is reached when heat loss exceeds heat release. Although internal transport limits the maximum temperature, the initial heating rate remains overestimated, suggesting that the initial phase is not solely limited by external oxygen diffusion, and the L2-gas surface is not at thermodynamic equilibrium. The model does not account for the particle size effect on maximum temperature as observed in some experiments. A hypothetical explanation is that internal convection, more pronounced in larger particles, may reduce the internal transport limitation, leading to higher maximum temperatures in larger particles.Novelty and significanceThis study advances the understanding of oxidation rate-limiting mechanisms in liquid iron particle combustion by numerically investigating the impact of internal transport within a core–shell structure. By using a two-dimensional axisymmetric transient continuum model, the research reveals that finite-rate internal transport significantly affects temperature evolution of an oxidizing micron-sized iron particle, particularly at elevated oxygen concentrations where it becomes rate-limiting. The findings demonstrate that a finite-rate internal transport leads to a higher local oxidation degree at the particle–gas interface, reducing the oxygen consumption rates. The study highlights that finite-rate internal transport limits the maximum particle temperature at elevated oxygen concentrations, a trend observed in isolated iron particle combustion experiments. Furthermore, this study provides a hypothetical explanation for the experimentally observed particle size effects on the maximum particle temperature, emphasizing the role of internal convection in larger particles

Dʺ Structures Beneath the East China Sea Resolved by P‐Wave Slowness Anomalies

AbstractThe Dʺ layer, defined as 200–400 km in the lowermost mantle, is a thermal and chemical boundary layer between the solid silicate mantle and the liquid outer core. Deciphering the detailed structures of the Dʺ region is essential for unlocking the thermal and chemical states in the deep Earth. Here, we precisely measure the slowness and back‐azimuth of the direct P‐waves by beamforming based on the F‐trace stack at the KZ Array in Kazakhstan, to investigate the detailed Dʺ structures beneath the East China Sea. The P‐wave slowness for rays turning beneath the East China Sea exhibits a significant anomaly as a function of the P‐wave turning depth. Strong correlations between slowness and back‐azimuth anomalies for rays from different directions suggest a tilted Moho, with a tilting direction of ∼103° and a dip angle of ∼15°, beneath the KZ Array, further supported by radial receiver functions. After correcting for the slowness anomalies caused by the tilted Moho and heterogeneities outside the Dʺ layer, we construct a series of Vp Dʺ models to fit the remaining slowness anomalies for rays sampling the East China Sea. We obtain the best Dʺ model with a height of 360 km, a maximum δVp of +1.4%, a Dʺ discontinuity thickness of 120 km, and an 80‐km low‐velocity layer at the base of the mantle by minimizing residuals between the predicted and observed slowness anomalies. Combining the sharpness of the Dʺ discontinuity imaged here with mineralogical analysis suggests a Fe‐enriched region in a cold subduction environment beneath the East China Sea.

Magnetic Taylor-Proudman Constraint Explains Flows into the Tangent Cylinder.

Tangent cylinders (TCs) have shaped our understanding of planetary dynamos and liquid cores. The Taylor-Proudman constraint creates these imaginary surfaces because of planetary rotation, separating polar and equatorial regions, but cannot explain the flows meandering through them. Here, we establish and verify experimentally that magnetic fields aligned with rotation drive flows into TCs, linked to the flows along TCs by a magnetic Taylor-Proudman constraint. This constraint explains and quantifies how magnetic fields reshape rotating flows in planetary interiors and magnetorotating flows in general.

Fabrication of hydrogel mini-capsules as carrier systems.

Conventional drug administration often results in systemic action, thus needing high dosages and leading to potentially pronounced side effects. Targeted delivery, employing carriers like nanoparticles, aims to release drugs at a target site, but only a small fraction of nanoparticles actually reaches it. Microrobots have been proposed to overcome this issue since they can be guided to hard-to-reach sites and locally deliver payloads. To enhance their functionality, we propose microrobots made as deformable capsules with hydrogel shells and aqueous cores, having the potential added advantages of biocompatibility, permeability, and stimulus-responsiveness. Endowing microrobots with deformability could allow them to navigate inside capillaries and cross barriers to finally reach the target site. In this study, we present a cost-effective method for fabricating core-shell structures without the use of organic solvents, surfactants, or extreme pH conditions unlike other techniques (e.g. Layer by Layer). The process begins with the dripping of a mixture of hydrogels, agarose and alginate, into a solution to gelate the drops into beads. After they are loaded with calcium ions at different concentrations, they are immersed in an alginate solution to form the shell. Finally, the beads are heated to let the agarose melt and diffuse out, leaving a liquid core. By varying the concentration of calcium ions, we obtain shells of different thicknesses. To estimate it, we have developed a method using the colour intensity from microscope images. This allowed us to observe that lowering the calcium ions concentration below a threshold does not lead to the formation of continuous shells. For higher concentrations, although the core may remain partially gelled, continuous shells successfully form. Therefore, our fabrication process could find applications in drug delivery, encapsulation systems, and microrobotics.

Encapsulation of Liquids via Polymer Precipitation in Emulsions

ABSTRACTMicroencapsulation strategies enable the confinement of sensitive active materials in a protective shell, giving capsules with applications across pharmaceuticals, foodstuffs, agriculture, textiles, cosmetics, and energy storage. Among the different approaches, the soft template encapsulation method is a widely used technique that leverages emulsions as templates and forms spherical microcapsules with a liquid core and polymeric shell. Within the emulsion template umbrella, interfacial polymerization, phase internal phase separation, and polymer precipitation can all be used. The main limitation of interfacial polymerization is that the core will inevitably contain impurities such as residual monomers, which can affect the performance of the encapsulated material. This is especially relevant when performance efficiency strongly depends on its pristine composition. In this perspective, we focus on polymer precipitation soft‐template strategies for capsule formation, and the complementarity of this approach to the more widely used interfacial polymerization. Polymer precipitation strategies enable the encapsulation of sensitive cores (or payloads) and can include those that are viscous, hygroscopic, and reactive.

Hydrodynamic analysis of core annular flow with a viscoplastic lubricant

Core annular flow (CAF) with viscoplastic lubrication (VPL) is an attractive proposition for pipeline transportation of high viscous oil, slurries and suspensions. Past studies have performed stability analysis to show that the unyielded zone at the liquid-liquid interface stabilizes CAF by suppressing interfacial instabilities. However, an in-depth investigation of the flow hydrodynamics and the conditions which reduce the pumping power within stable CAF range using VPL has not been reported till date. Moreover, most of the studies have considered a Bingham Plastic liquid in the annulus. Only a single study (Usha & Sahu, 2019) is reported with Herschel-Bulkley (HB) liquid in the annulus that considers the entire annulus to be in the shear zone. Another experimental study (Huen et al., 2007) has demonstrated stable core annular flow with a shear thinning core and a HB annulus. In the present work, we analyze viscoplastically lubricated CAF for a Newtonian core where the yield stress annular liquid is described by the generalized HB model. The simplified analysis can predict CAF stability and is further explored to (i) assess the efficacy of VPL for stable energy-efficient oil transportation, and (ii) enhanced throughput without clogging during suspension transportation. The analysis, validated against data from literature, unravels the influence of rheological properties on flow hydrodynamics. We note that an annular liquid with low flow behavior index, n and yield stress, τy lowers pumping power, but the yield stress should be sufficient to form a plug zone at the interface for suppressing instabilities and stabilizing CAF. For viscous oil, a phase diagram in dimensionless coordinates (Reynolds number of the oil core and Herschel-Bulkley number of the annular liquid, both expressed at the inlet conditions) suggests the range of operation where an available HB liquid can serve as an effective annular lubricant for energy-efficient transportation.

Five-dimensional compact stars in Einstein-Gauss-Bonnet gravity

Within the framework of Einstein-Gauss-Bonnet theory in five-dimensional spacetime (5D EGB), we derive the hydrostatic equilibrium equations and solve them numerically to obtain neutron stars for both isotropic and anisotropic distribution of matter. The mass-radius relations are obtained for SLy equation of state, which describes both the solid crust and the liquid core of neutron stars, and for a wide range of the Gauss-Bonnet coupling parameter α. More specifically, we find that the contribution of the Gauss-Bonnet term leads to substantial deviations from Einstein gravity. We also discuss that after a certain value of α, the theory admits higher maximum masses compared with general relativity, however, the causality condition is violated in the high-mass region. Finally, our results are compared with the recent observations data on mass-radius diagram.

A subchannel analysis code for advanced liquid metal fast reactor cores and study on heat transfer characteristics of core geometry parameters

The liquid metal fast reactor represents an important reactor type for the future development of nuclear energy. Accurately modeling and predicting the subchannel flow and heat transfer phenomenon in the rod bundles plays a key role in ensuring core safety. Consequently, a subchannel code suitable for the liquid metal fast reactor is analyzed based on the subchannel analysis code of the Pressurized Water Reactor (PWR). The modified code incorporates various types of liquid metals, such as lead, lead-bismuth eutectic (LBE), and sodium, along with their constitutive models, enhancing the applicability of the liquid metal reactor systems. This code has been verified and validated at several levels, including comparing the code simulation results with other similar subchannel codes results, high-dimensional Computational Fluid Dynamics (CFD) simulations, and experiment data. The sensitivity analysis of core geometric parameters and turbulent mixing coefficients is performed based on the modified version code. The influence of the core geometry, including the rod Pitch to Diameter ratio (P/D), Rod to Wall gap (RTW) and the wire wrap pitch (H) on the sensitivity of outlet temperature has been investigated. The results show that the new subchannel analysis code suitable for liquid metal cooled reactor shows reasonable agreement with the verified and validated results. The geometric parameters, such as P/D, RTW and H have noticeable effects on the outlet temperature difference of the subchannels. Additionally, the outlet temperature distribution in the subchannel is significantly affected by different turbulent mixing coefficients and the distribution of the turbulent mixing coefficient also influenced by the reactor core sizes. Overall, this study could support the rod bundles design and safety analysis in the liquid metal reactors.