Liquid Encapsulation Research Articles

A versatile multilayer liquid–liquid encapsulation technique

HypothesisGenerating multi-layer cargo using conventional methods is challenging. We hypothesize that incorporating a Y-junction compound droplet generator to encase a target core inside a second liquid can circumvent the kinetic energy dependence of the impact-driven liquid-liquid encapsulation technique, enabling minimally restrictive multi-layer encapsulation. ExperimentsStable wrapping is obtained by impinging a compound droplet (generated using Y-junction) on an interfacial layer of another shell-forming liquid floating on a host liquid bath, leading to double-layered encapsulation. The underlying dynamics of the liquid-liquid interfaces are captured using high-speed imaging. To demonstrate the versatility of the technique, we used various liquids as interfacial layers, including magnetoresponsive oil-based ferrofluids. Moreover, we extended the technique to triple-layered encapsulation by overlaying a second interfacial layer atop the first floating interfacial layer. FindingsThe encapsulating layer(s) effectively protects the water-soluble inner core (ethylene glycol) inside the water bath. A non-dimensional experimental regime is established for successful encapsulation in terms of the impact kinetic energy, interfacial layer thickness, and the viscosity ratio of the interfacial layer and the outer core liquid. Using selective fluorescent tagging, we confirm the presence of individual shell layers wrapped around the core, which presents a promising pathway to visualize the internal morphology of final encapsulated droplets.

Synergistic ionic liquid encapsulated MIL-101 (Cr) metal-organic frameworks for an innovative adsorption desalination system

The transformations of brackish water into freshwater employing porous materials such as metal-organic frameworks (MOFs) show a great potential for a green environment. But the adsorption-based desalination slows down due to slow water adsorption/desorption rates and inadequate water storage capacity in conventional adsorbents. Therefore, the restructuring of porous MOFs increases water storage and transfer rates. This paper presents a comprehensive investigation on the fabrication of ionic liquid encapsulated MIL-101 (Cr) MOFs (metal-organic frameworks), and its interactions with water for desalination applications. Firstly, the pristine MIL-101 (Cr) is encapsulated with various types/amounts of ionic liquids. Next, these MOFs are characterized via SEM (Scanning electron microscope), FTIR (Fourier transform infrared), XRD (X-ray diffraction), TGA (Thermal gravimetric analysis), N2 adsorption techniques. The water adsorption on these MOFs is performed experimentally for a wide temperature (30–80 °C) and pressure (0 < P/Ps < 0.95) ranges. The effects of the size (or type) as well as the encapsulation ratio of ionic liquids on water adsorption behaviors are conducted. Based on the experimentally proven water adsorption (isotherms and kinetics) data, an AD (adsorption desalination) system is modelled and simulated. Finally, the AD performances in terms of the specific daily water production (SDWP) and performance ratio (PR) are parametrically studied with respect to various regeneration temperature (50–80 °C) and cycle times (100 s–1000 s). It is found that by ionic liquid encapsulation, the water uptakes/offtake rates are expedited up to 48% (for adsorption)/55% (for desorption), respectively. In addition, the water transfer (Δq) improves up to 45% more than the parent MIL-101(Cr) MOFs. Furthermore, the SDWP increases from 38 to 56 m3 of water per tonne of MOFs per day at the regeneration temperature of 70 °C. The simulation results also show that the ionic-liquid-encapsulated MIL-101 (Cr) MOFs generates water (>25 m3 water per tonne of IL-MOFs) at the regeneration temperature of 50 °C and is potential for the next generation desalination applications.

Insight into the stabilization mechanism of Zn during co-gasification of sewage sludge and coal: Perspective of solid-liquid transition

In this study, the underlying mechanism of zinc (Zn) stabilization during the co-gasification of sewage sludge (SS) with Shenmu coal (SM) was investigated using an in-situ visual furnace to analyze the distribution of Zn species. The findings classified two distinct stages within the co-gasification process: the organic matter gasification stage, occurring below 1000 °C, and the inorganic mineral melting stage, occurring above 1000 °C. The addition of SM can extend the organic matter gasification phase, in which the porous carbon structure of the SM char aids in the capture of Zn released during the devolatilization of SS. However, a sustained reducing atmosphere promoted the formation of Fe3O4, causing Zn destabilization. Subsequently, during the inorganic mineral melting stage, the complete reaction of carbon released Zn, which was adsorbed onto the carbon surface. Furthermore, the ash from SM contributes to the melting of the co-gasification residues, enhancing Zn stabilization through encapsulation by the molten phase and stabilization within the spinel lattice. This study highlights the critical role of liquid encapsulation in Zn stabilization during co-gasification.

Water-Templated Growth of Interfacial Superglue Polymers for Tunable Thin Films and In Situ Fluid Encapsulation.

Thin polymer films (TPFs) are indispensable elements in numerous technologies ranging from liquid encapsulation to biotechnology to electronics. However, their production typically relies on wet chemistry involving organic solvents or chemical vapor deposition, necessitating elaborate equipment and often harsh conditions. Here, an eco-friendly, fast, and facile synthesis of water-templated interfacial polymers based on cyanoacrylates (superglues, CAs) that yield thin films with tailored properties is demonstrated. Specifically, by exposing a cationic surfactant-laden water surface to cyanoacrylate vapors, surfactant-modulated anionic polymerization produces a manipulable thin polymer film with a thickness growth rate of 8nmmin-1. Furthermore, the shape and color of the film are precisely controlled by the polymerization kinetics, wetting conditions, and/or exposure to patterned light. Using various interfaces as templates for film growth, including the free surface of drops and soap bubbles, the developed method advantageously enables in situ packaging of chemical and biological cargos in liquid phase as well as the encapsulation of gases within solidified bubbles. Simple, versatile, and biocompatible, this technology constitutes a potent platform for programmable coating and soft/smart encapsulation of fluids.

Study on Rock Interface Stability in the Heat Exchange Channel of the Horizontal Section of U-Shaped Wells in Hot Dry Rock

Enhanced Geothermal Systems (EGS) represent a promising direction for sustainable energy development, yet their efficiency and feasibility often suffer due to suboptimal heat extraction methods and interface instability in U-shaped wells. This study introduces an innovative volume encapsulation technology that aims to address these challenges. The proposed technology employs a combination of hydraulic fracturing and acidification to prepare the rock interface, followed by encapsulation using high-temperature liquid metal. Low-melting-point alloys are utilized as a heat exchange medium between the horizontal sections of the wells. This study meticulously analyzes the impact of formation stress, thermal shock stress, and liquid metal properties on rock interface stability. Advanced simulation tools and experimental setups were used to test the encapsulation process under various conditions. The application of liquid metal encapsulation demonstrated significant improvements in energy conversion efficiency and rock interface stability. In conditions simulating a dry and hot rock reservoir at depths up to 3000 m and temperature gradients reaching 2200 °C/m, the adjusted depth of horizontal sections and increased pumping pressure contributed to maintaining interface stability. The established failure criteria provide a robust theoretical foundation for the encapsulation process. Volume encapsulation technology using liquid metal not only enhances the operational efficiency of EGS but also stabilizes the rock interface, thereby increasing the feasibility of continuous geothermal energy extraction. This study offers valuable theoretical insights and practical guidance for future research and applications in geothermal energy technologies, creating new pathways for the efficient exploitation of geothermal resources.

Immobilization mechanism of Mn2+ in electrolytic manganese residue using sintered ceramsites prepared by alkali-mechanical-roasting method

Currently, sufficient information is unavailable on using electrolytic manganese residue (EMR) to prepare sintered ceramsites for immobilization of manganese in EMR. This study used EMR, Na2CO3, and montmorillonite (MMT) as raw materials to prepare ceramsites with the influence of alkalinity, sintering temperature, and sintering time on the investigated ceramsite properties. Under the optimal conditions (i.e., C-2 h= EMR content: 50%, Na2CO3 content: 25%, sintering temperature: 1050℃, sintering time: 2 h), the cylinder compressive strength, porosity, bulk density and apparent density of the ceramsites reached 25.03 MPa, 54.72%, 0.748 g/cm3 and 2.056 g/cm3. The presence of mesoporous pores within the ceramsites made them suitable for adsorption as biocarriers. The leaching concentration of Mn2+ from the ceramsites was 2.26 mg/L, lower than the third grade in standard (GB 8978–1996), suggesting that heavy metals are stabilized within the ceramsite. The main immobilization mechanism in the ceramsites included the formation of a new crystalline phase including jacobsite (Fe2MnO4) and liquid phase encapsulation. The involvement of certain impurities such as Mg2+ in the formation of crystalline phases can influence Mn2+ immobilization. This research not only offers valuable insights into the safe and valuable utilization of EMR but also provides a novel method for preparing ceramsites.

CO2 capturing by self-assembled belt[14]pyridine encapsulated ionic liquid complexes: a DFT study.

In the current study, CO2 capturing ability of encapsulated ionic liquids (ENILs) i.e., tetramethylammonium chloride (TMACl), 1,3-dimethylimidazolium chloride (MIMCl), and methylpyridinium hexafluorophosphate (MPHP) encapsulated in self assembled belt[14]pyridine (BP) has been studied. The results show that strong van der Waals forces are involved in capturing of CO2 by these encapsulated ionic liquids. Strong attractive forces arise from synergistic effect of ionic liquid (encapsulated) and atoms of belt. The interaction energies (E int) ranging from -12.54 to -18.64 kcal mol-1 reveal the capturing of CO2 by these systems as thermodynamically feasible process. The type and strength of interactions between CO2 and encapsulated ionic liquids is studied through QTAIM and NCI analyses. NCI analysis clearly shows that capturing of CO2 is assisted by van der Waals forces between CO2 and encapsulated ionic liquid complexes. The same feature is confirmed through QTAIM analysis as well. Natural bond orbital (NBO) analysis' results show the charge transfer between the fragments (encapsulated ionic liquids and CO2) which is validated further through electron density differences (EDD) analysis. Overall, transfer of charge towards CO2 from encapsulated ionic liquids is proved through the charge accumulation over CO2 (i.e., blue isosurfaces on CO2 molecules) through EDD analysis. The FMO analyses show the decrease in H-L gaps of encapsulated ionic liquids after CO2 capturing. The successful charge transfer and reduction in H-L gap indicate better interaction in the designed systems thus revealing these systems as a potential candidates for CO2 capturing. Overall, the best results for CO2 capture i.e., the highest interaction energy, the lowest H-L gap, and the strongest forces of interactions are shown by methylpyridinium hexafluorophosphate (MPHP) encapsulated belt[14]pyridine (BP-MPHP) system. This is due to the larger anion of methylpyridinium hexafluorophosphate as compared to the other two encapsulated ionic liquids with Cl- as anion which enables it to develop strong interactions with CO2. The designed belt[14]pyridine based encapsulated ionic liquid systems are promising prospects with better CO2 capture performance and represent a new entrant in the CO2 capturing systems.

Tunable encapsulation of sessile droplets with solid and liquid shells

Droplet encapsulations using liquid or solid shells are of significant interest in microreactors, drug delivery, crystallization, and cell growth applications. Despite progress in droplet-related technologies, tuning micron-scale shell thickness over a large range of droplet sizes is still a major challenge. In this work, we report capillary force assisted cloaking using hydrophobic colloidal particles and liquid-infused surfaces. The technique produces uniform solid and liquid shell encapsulations over a broad range (5–200 μm shell thickness for droplet volume spanning over four orders of magnitude). Tunable liquid encapsulation is shown to reduce the evaporation rate of droplets by up to 200 times with a wide tunability in lifetime (1.5 h to 12 days). Further, we propose using the technique for single crystals and cell/spheroid culture platforms. Stimuli-responsive solid shells show hermetic encapsulation with tunable strength and dissolution time. Moreover, scalability, and versatility of the technique is demonstrated for on-chip applications.

Flexible fluid-based encapsulation platform for water-sensitive materials

The next-generation semiconductors and devices, such as halide perovskites and flexible electronics, are extremely sensitive to water, thus demanding highly effective protection that not only seals out water in all forms (vapor, droplet, and ice), but simultaneously provides mechanical flexibility, durability, transparency, and self-cleaning. Although various solid-state encapsulation methods have been developed, no strategy is available that can fully meet all the above requirements. Here, we report a bioinspired liquid-based encapsulation strategy that offers protection from water without sacrificing the operational properties of the encapsulated materials. Using halide perovskite as a model system, we show that damage to the perovskite from exposure to water is drastically reduced when it is coated by a polymer matrix with infused hydrophobic oil. With a combination of experimental and simulation studies, we elucidated the fundamental transport mechanisms of ultralow water transmission rate that stem from the ability of the infused liquid to fill-in and reduce defects in the coating layer, thus eliminating the low-energy diffusion pathways, and to cause water molecules to diffuse as clusters, which act together as an excellent water permeation barrier. Importantly, the presence of the liquid, as the central component in this encapsulation method provides a unique possibility of reversing the water transport direction; therefore, the lifetime of enclosed water-sensitive materials could be significantly extended via replenishing the hydrophobic oils regularly. We show that the liquid encapsulation platform presented here has high potential in providing not only water protection of the functional device but also flexibility, optical transparency, and self-healing of the coating layer, which are critical for a variety of applications, such as in perovskite solar cells and bioelectronics.

Structure-Property Relationships of CO2 Absorbing Core-Shell Microparticles with Encapsulated Ionic Liquid.

The demand for new ionic liquid (IL)-based systems to selectively sequester carbon dioxide from gas mixtures has prompted the development of individual components involving the tailored design of IL themselves or solid-supported materials that provide excellent gas permeability of the overall material as well as the ability to incorporate large amounts of ionic liquid. In this work, novel IL-encapsulated microparticles comprising a cross-linked copolymer shell of β-myrcene and styrene and a hydrophilic core of the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) are proposed as viable materials for CO2 capture. Water-in-oil (w/o) emulsion polymerization of different mass ratios of β-myrcene to styrene (i.e. 100/0, 70/30, 50/50, 0/100) yielded IL-encapsulated microparticles, where the encapsulation efficiency of [EMIM][DCA] was dependent on the copolymer shell composition. Thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that both thermal stability and glass transition temperatures depend on the mass ratio of β-myrcene to styrene. Images from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microparticle shell morphology as well as measure the particle size perimeter. Particle sizes were found to be between 5 and 44 μm. CO2 sorption experiments were conducted gravimetrically using TGA instrumentation. Interestingly, a trade-off between CO2 absorption capacity and ionic liquid encapsulation was observed. While increasing the β-myrcene content within the microparticle shell increases the amount of encapsulated [EMIM][DCA], the observed CO2 absorption capacity did not increase as expected due to reduced porosity compared to microparticles with higher styrene content in the microparticle shell. [EMIM][DCA] microcapsules with a 50/50 weight ratio of β-myrcene/styrene showed the best synergistic effect between spherical particle diameter (32.2 μm), pore size (0.75 μm), and high CO2 sorption capacity of ∼0.5 mmol CO2/g sample within a short absorption period of 20 min. Therefore, core-shell microcapsules composed of β-myrcene and styrene are envisioned as a promising material for CO2 sequestration applications.

Nanoliter Liquid Packaging in a Bioresorbable Microsystem by Additive Manufacturing and its Application as a Controlled Drug Delivery Device

AbstractPrecise packaging of nanoliter amounts of liquid in a microsystem is important for many biomedical applications. However, existing liquid encapsulation technologies have limitations in terms of liquid waste, evaporation, trapped bubbles, and liquid degradation. In this study, multiple additive manufacturing techniques for nanoliter liquid packaging in bioresorbable microsystems is used. Two‐photon photolithography is used for bioresorbable reservoir fabrication, while inkjet printing (IJP) is used for precise nanoliter liquid packaging. Dual IJP allows for micro‐reservoirs to be filled with precise amounts of drug solution and subsequently and rapidly sealed with a layer of lipids mixed with Fe3O4 nanoparticles. Combining these two printing techniques can overcome the previous limitations of liquid encapsulation technologies. To demonstrate the relevance of this technique, a wirelessly activated, bioresorbable multi‐reservoir microcapsule that can be used for controlled drug delivery is presented. The microcapsules and their content are shown to be stable during fabrication, storage, and operation. Multiple cargo release events are triggered independently by the local melting of the sealing layer, resulting from magnetically induced Fe3O4 nanoparticle heating. The operation of the capsule is demonstrated in tissue phantoms and in vitro cell cultures.

Preprogramming Floating Time of Liquid Marble

AbstractNon‐sticking droplets wrapped with fine hydrophobic particles, namely liquid marbles, can be transported both on solid and water pool without an undesired spill of the inner encapsulated liquid. While the stimuli‐responsive release of the inner liquid in the target area is proposed, the time‐programmed release is not yet achieved. Herein, the hydrophobicity of nanoclay is modulated via a catalyst‐free 1,4‐conjugate addition reaction to form liquid marbles. This nanoclay liquid marble is robust and stable in air but collapses on the liquid pool with a specific lifetime. The lifetime of the liquid marble can be modulated over seconds to hours scale depending on the selection of chemically modulated wettability of the nanoclay. The critical mechanism of lifetime modulation is responsible for controlling the coalescence kinetics between the water pool and inner liquid by nanoclays’ high diffusion length and chemically varied water spreading potential. The NC liquid marble's programmable lifetime to ‘time‐bomb’ type drug release and cascade chemical reaction is applied—without requiring any external intervention.

Optimization of coating ratio and homogenization conditions in the production of coconut shell liquid smoke nanoparticles

The liquid smoke in liquid form is considered less practical and susceptible to damage to phenolic compounds during storage. Liquid smoke encapsulation technology is expected to be able to overcome the problem of handling liquid smoke. This study aimed to determine the optimum conditions for the manufacture of liquid smoke nanoparticles in terms of the particle size distribution produced. The ratio of arabic gum and maltodextrin concentration, homogenization speed and homogenization time were optimized using the Box-Behnken Response Surface Methodology (RSM) experimental design. The response used in this study is the particle size distribution (z-average). Based on the results of the study, the optimum conditions for the manufacture of liquid smoke nanoparticles were obtained at a concentration ratio of gum arabic and maltodextrin 12:88, a homogenization speed of 4000 rpm and a homogenization time of 3 mins, with a particle size distribution (z-average) 78.53±1.48 nm.

The Rising Aerogel Fibers: Status, Challenges, and Opportunities.

Aerogel fibers garner tremendous scientific interest due to their unique properties such as ultrahigh porosity, large specific surface area, and ultralow thermal conductivity, enabling diverse potential applications in textile, environment, energy conversion and storage, and high-tech areas. Here, the fabrication methodologies to construct the aerogel fibers starting from nanoscale building blocks are overviewed, and the spinning thermodynamics and spinning kinetics associated with each technology are revealed. The huge pool of material choices that can be assembled into aerogel fibers is discussed. Furthermore, the fascinating properties of aerogel fibers, including mechanical, thermal, sorptive, optical, and fire-retardant properties are elaborated on. Next, the nano-confining functionalization strategy for aerogel fibers is particularly highlighted, touching upon the driving force for liquid encapsulation, solid-liquid interface adhesion, and interfacial stability. In addition, emerging applications in thermal management, smart wearable fabrics, water harvest, shielding, heat transfer devices, artificial muscles, and information storage, are discussed. Last, the existing challenges in the development of aerogel fibers are pointed out and light is shed on the opportunities in this burgeoning field.

Nanostructured steady-state nanocarriers for nutrients preservation and delivery.

Food bioactives possess specific physiological benefits of preventing certain diet-related chronic diseases or maintain human health. However, the limitations of the bioactives are their poor stability, lower water solubility and unacceptable bioaccessibility. Structure damage or degradation is often found for the bioactives under certain environmental conditions like high temperature, strong light, extreme pH or high oxygen concentration during food processing, packaging, storage and absorption. Nanostructured steady-state nanocarriers have shown great potential in overcoming the drawbacks for food bioactives. Various delivery systems including solid form delivery system, liquid form delivery system and encapsulation technology have been developed. The embedded food nutrients can largely decrease the loss and degradation during food processing, packaging and storage. The design and application of stimulus and targeted delivery systems can improve the stability, bioavailability and efficacy of the food bioactives upon oral consumption due to enzymatic degradation in the gastrointestinal tract. The food nutrients encapsulated in the smart delivery system can be well protected against degradation during oral administration, thus improving the bioavailability and releazing controlled or targeted release for food nutrients. The encapsulated food bioactives show great potential in nutrition therapy for sub-health status and disease. Much effort is required to design and prepare more biocompatible nanostructured steady-state nanocarriers using food-grade protein or polysaccharides as wall materials, which can be used in food industry and maintain the human health.

Construction of ionic liquid-filled silica shell microcapsules based on emulsion template and evaluation of their adsorption properties toward 3,4,5-trichlorophenol after various surface functionalization

The development of environmentally friendly and efficient methods for the removal of Phenolic endocrine disruptors (PEDs) from aqueous is essential to protect the environment and human health. In this work, sol–gel method and emulsion template approach were combined and applied to construct 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid-filled silica-shell microcapsules (SiO2@IL). And amino, halogen and long-chain alkanes surface-functionalized silica-shell encapsulated ionic liquid microcapsules (SiO2-NH2@IL, SiO2-Cl@IL, and SiO2-C16@IL) were successfully formulated by silica layer modification techniques. The microcapsules have homogeneous dimensions, about 1 µm, and high loading, about 92 wt% of ILs. Four microcapsules showed high adsorption properties and excellent regeneration performance for removing 3,4,5-trichlorophenol (3,4,5-TCP), which benefited from the excellent performance of [BMIM]PF6 on the extraction of 3,4,5-TCP and the enhanced hydrophobic and electrostatic effects of the surface modified microcapsules. The maximum adsorption capacity of SiO2@IL, SiO2-NH2@IL, SiO2-Cl@IL and SiO2-C16@IL calculated from the Langmuir model was 1047, 1207, 1108 and 1145 mg g−1 at 25 °C, respectively. The main factors affecting the extraction performance were the hydrophobicity and steric hindrance of [BMIM]PF6. After three regeneration cycles, the adsorption capacity and desorption efficiency of microcapsules were still above 90 %. The functionalization of the shell layer enhances the hydrophobic and electrostatic effects, which is conducive to the adsorption process, and provides some theoretical and data support for the subsequent construction of ionic liquid encapsulation materials for chlorophenol removal.

(Invited) Kinetics and Thermodynamics of Swcnts and Bnnts Encapsulation with α-Sexithiophene in Liquid Phase

Single-Walled Carbon Nanotubes (SWNTs) and Boron Nitride Nanotubes (BNNTs) come with hollow 1D centers, which can serve to define narrow spaces for encapsulating small organic dyes. The encapsulation process is of scientific interest because it can be used to tailor the optical properties of the resulting dyes@NTs nanohybrids. Past works have shown that the dyes@SWCNT exhibits a strongly enhanced Raman scattering cross section, while the dyes@BNNTs do emit robust, generally red-shifted, luminescence at wavelengths down to the near-IR. In both cases, the nanotube protects the encapsulated dyes from photobleaching, provides high confinement, and reinforces intermolecular interactions between dyes into specific aggregation states.Here, we compare the liquid phase encapsulation process of α-sexithiophene (6T), which is a conjugated rod-like dye, inside SWCNTs and BNNTs. Raman and luminescence imaging experiments are used to monitor the 6T encapsulation process of a large ensemble of individual nanotubes in liquid-phase. This method probes statistically the encapsulation kinetics using hundreds of individual nanotubes according to various parameters (dye concentration and temperature). The results highlight a kinetic model in which single and double aggregates is formed sequentially. This kinetics and the associated thermodynamic parameters for the 6T encapsulation will be presented and discussed so as to gain a better control over the emission properties of the nanohybrids.

Enkapsulasi Asap Cair Tandan Kosong Kelapa Sawit (Elaeis guineensis Jacq.) dan Uji Aktivitas Antijamur

Oil palm empty bunches is lignocellulose that can be processed into liquid smoke with the content of acid compounds and phenol compounds that function as a natural preservative. The purpose of this study to find out the characteristics of liquid smoke, see the effect of encapsulan on the liquid smoke encapsulation process, and see the antifungal activity of A. flavus and A. niger. The method used is pyrolysis process at a temperature of 400 oC to produce liquid smoke and encapsulation process by using variation of coating material using spray dryer with micro sized result. The result showed that the liquid smoke characteristics can be seen from its chemical content that is the dominant phenol compound and has the highest phenol content among the parts found in oil palm that is 68,15%. Based on analysis it can be seen that the best encapsulation process is by the addition of chitosan on maltodextrin with water content 5.78%, phenol content of 43.03 ppm and has a high rate of encapsulation efficiency of 45.87%. The liquid smoke microcapsules could inhibit the growth of fungi with the highest value of liquid smoke concentration, that is 3% with inhibitory value of 8.30 mm.

Thermal and optical performance characterization of bare and phosphor converted LEDs through package level immersion cooling

Increased demand for high flux electronics requires creative and affordable thermal management approaches to meet the performance and lifetime expectations. In the present study, optical and thermal improvements of a new package level liquid coolant encapsulation that directly targets heat generation zones are studied for bare and phosphor converted LEDs. As heat both at chip and phosphor composite regions are being generated, a series of detailed experimental and theoretical characterization is performed in order to examine the capability of the new cooling method. The findings can be used to extend the application of precisely controlled liquid packing on the heat source region of optoelectronic components. This method has shown a 15% reduction in thermal resistance and a 7% increase in power conversion efficiency of LED packages. The capacity of this method is mainly limited to the thermal conductivity of the coolant while a significant ability for improvement can be expected by utilizing thermally conductive particles such as hexagonal boron nitride inside the coolant.

Drop-on-demand printing of recyclable circuits by partially embedding molten metal droplets in plastic substrates

Recyclable electronics are important in green manufacturing and sustainable development, but in infancy, printing strategies still need more exploration and improvement. Metal drop-on-demand (DOD) printing is an ideal candidate for fabricating recyclable circuits, owing to its advantage of inherent direct recyclable feedstocks. Liquid metals with melting points at room temperature have been utilized to print circuits. However, developing liquid metal-based composites or encapsulation is still needed to maintain shapes of printed patterns and improve the adhesion between liquid metals and substrates, restricting the directly recycling of printed circuits. Herein, tin solder is utilized to directly print recyclable circuits via metal drop-on-demand printing method. The molten tin solder droplets directly melt plastic substrates and partially embed the substrate to obtain good adhesion. Molten droplets solidify timely to maintain the shapes of printed 2D conductive patterns and 3D microstructures without encapsulation. Moreover, the electrical conductivity of printed lines is close to the homogeneous bulk metal due to the direct metallurgical bonding between droplets. The conductive traces can be directly recycled by mechanically peeling from the substrate and remelting in the crucible. To validate this concept, a 555 circuit is successfully printed and recycled to fabricate a new 3D cross circuit. This work opens a new direction to directly fabricate recyclable circuits by using metal drop-on-demand printing.