Core-shell Particles Research Articles

How do the core mechanical properties affect the toughening of polypropylene with core-shell particles?

How do the core mechanical properties affect the toughening of polypropylene with core-shell particles?

Optical Spectra of Plasmon–Exciton Core–Shell Nanoparticles: A Heuristic Quantum Approach

Light–matter coupling in plasmonic nanocavities has been widely studied in the past years. Yet, for core–shell particles, popular electromagnetic models that use the classical Lorentz oscillator to describe the shell predict extinction spectra with three maxima, if the plasmon and the shell absorption are in resonance. In contrast, experiments exhibit only two peaks, as also expected from simple quantum models of hybrid states. In order to reconcile the convenient and widely used classical electromagnetic description with experimental data, we connect it to the quantum world by conceiving a heuristic quantum model. Our model is based on the permittivity of a two-level system in a classical electric field derived from the optical Bloch equations. The light–matter coupling is included via the collective vacuum Rabi frequency Ω0. Using our model, we obtain excellent agreement with a series of experimental extinction spectra of particles with various coupling strengths due to a systematic size variation. The suppression of the third maximum, which mainly stems from the absorption in the shell, can be interpreted as a vacuum induced power broadening, which may occur in lossy (plasmonic) cavities below the strong-coupling regime.

Mixing gold and iron in nanoparticles by electrical discharges in liquid: A new approach

The possibility to create homogeneous nanoparticles containing iron and gold by nanosecond-pulsed discharges in liquids, without any laser assistance, is demonstrated. Thanks to a new kind of electrode where elements are coated by PVD on a silicon plate, AuFe nanoparticles, ranging from 10 to 50 nm, are synthesized. Depending on their residence time in the discharge, the structure of the homogeneous nanoparticles evolves to become a core–shell structure, either nested or not. Larger submicrometric particles (from 100 to 500 nm) are specifically formed with the present process by the ejection of liquid droplets from the molten pool created by the discharge on electrode surfaces. These larger particles are produced by solidification of a AuFe shell on a silicon core. This new mechanism can be used to create core–shell particles with a shell containing several, possibly immiscible, elements. Thermal post-treatment performed in situ in a TEM microscope shows the AuFe shell, where Au and Fe separate, turning either into a Janus structure or into a SiFe core facetted by gold pyramids.

Hollow Particles Obtained by Prilling and Supercritical Drying as a Potential Conformable Dressing for Chronic Wounds.

The production of aerogels for different applications has been widely known, but the use of polysaccharide-based aerogels for pharmaceutical applications, specifically as drug carriers for wound healing, is being recently explored. The main focus of this work is the production and characterization of drug-loaded aerogel capsules through prilling in tandem with supercritical extraction. In particular, drug-loaded particles were produced by a recently developed inverse gelation method through prilling in a coaxial configuration. Particles were loaded with ketoprofen lysinate, which was used as a model drug. The core-shell particles manufactured by prilling were subjected to a supercritical drying process with CO2 that led to capsules formed by a wide hollow cavity and a tunable thin aerogel layer (40 μm) made of alginate, which presented good textural properties in terms of porosity (89.9% and 95.3%) and a surface area up to 417.0 m2/g. Such properties allowed the hollow aerogel particles to absorb a high amount of wound fluid moving very quickly (less than 30 s) into a conformable hydrogel in the wound cavity, prolonging drug release (till 72 h) due to the in situ formed hydrogel that acted as a barrier to drug diffusion.

Upper critical solution temperature polymer assemblies via variable temperature liquid phase transmission electron microscopy and liquid resonant soft X-ray scattering

Here, we study the upper critical solution temperature triggered phase transition of thermally responsive poly(ethylene glycol)-block-poly(ethylene glycol) methyl ether acrylate-co-poly(ethylene glycol) phenyl ether acrylate-block-polystyrene nanoassemblies in isopropanol. To gain mechanistic insight into the organic solution-phase dynamics of the upper critical solution temperature polymer, we leverage variable temperature liquid-cell transmission electron microscopy correlated with variable temperature liquid resonant soft X-ray scattering. Heating above the upper critical solution temperature triggers a reduction in particle size and a morphological transition from a spherical core shell particle with a complex, multiphase core to a micelle with a uniform core and Gaussian polymer chains attached to the surface. These correlated solution phase methods, coupled with mass spectral validation and modeling, provide unique insight into these thermoresponsive materials. Moreover, we detail a generalizable workflow for studying complex, solution-phase nanomaterials via correlative methods.

Self-Cleaning and Photodegradable PVDF-g-IL Dye Wastewater Separation Membranes Modified with Dopamine-Coated TiO2 Core-Shell Particles.

In the present work, self-cleaning membranes of ionic liquid-grafted poly(vinylidene fluoride) (PVDF) polydopamine-coated TiO2 were prepared through a nonsolvent-induced phase separation method. PDA facilitates the uniform dispersion of TiO2 nanoparticles in PVDF substrates; meanwhile, TiO2@PDA core-shell particles and the hydrophilic IL improve the hydrophilicity of PVDF membranes and contribute to the increased average pore size and porosity, significantly improving the pure water permeation flux and dye wastewater flux (the water flux increased to 385.9 Lm-2 h-1). In addition, the combined effect of the positively charged IL and the strongly viscous PDA shell layer enhanced the retention and adsorption of dyes so that the retention and adsorption rates of both anionic and cationic dyes were close to 100%. Notably, the hydrophilic PDA allowed more TiO2 to migrate to the membrane surface during the phase transition; on the other hand, dopamine could promote photodegradation. Therefore, the combined two factors for TiO2@PDA were beneficial to the ultraviolet-catalytic (UV-catalytic) degradation of dyes on the surface of the membrane, leading to >80% degradation rates of various dyes. Thus, the high-efficiency and easy-to-operate wastewater treatment technology provides attractive potential for dye removal and resolution of membrane contamination.

Atom Transfer Radical Polymerization of 2-Isopropenyl-2-Oxazoline in Solution and from the Surface of Carbonyl Iron Particles toward Fabrication of a Cytocompatible Magneto-Responsive Hybrid Filler

Atom transfer radical polymerization (ATRP) of 2-isopropenyl-2-oxazoline was optimized both in solution and initiated from carbonyl iron (CI) particle surface (SI-ATRP) in order to obtain polymers with well-defined molar mass and narrow dispersity. The polymerization procedure was thoroughly investigated by size exclusion chromatography and 1H NMR and optimized from the point of view type of initiator, ligand, copper catalyst, and solvent. Finally, the poly(2-isopropenyl-2-oxazoline) (PIPOx) with controlled molar masses up to 20,000 g/mol and dispersity in the range of 1.2–1.5 were successfully prepared, while high conversions could be reached. Polymerization conditions using halogen exchange leading to well-defined PIPOx were also developed and used for SI-ATRP. SI-ATRP was finally applied for synthesis of magnetic CI-PIPOx core–shell particles with two various molar masses of the grafted PIPOx. Finally, as a proof of applicability of such hybrid particles, the particles were dispersed in the phosphate buffer saline and glycerol to obtain the magnetorheological fluid with blood-like characteristics. Magnetorheological and cytotoxicity investigations proved that non-cytotoxic CI-PIPOx core–shell particles provided the system with sufficient yield stress values to act as an embolization agent.

Comparison of nanofibers, microfibers, nano/microfiber graphene doped composites, molecularly imprinted polymers, and restricted access materials for on-line extraction and chromatographic determination of citrinin, zearalenone, and ochratoxin A in plant-based milk beverages

Several advanced sorbents for on-line extraction followed by chromatographic determination of citrinin, zearalenone, and ochratoxin A in a complex matrix of plant-based beverages from oat and rice milk have been compared. Twelve types of the fibrous sorbents, including polyethylene and polypropylene microfibers, polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite, poly(3-hydroxybutyrate) microfibers, poly(3-hydroxybutyrate) microfibers/polypropylene microfibers composite, polycaprolactone nanofibers, polycaprolactone nanofibers doped with 7.7, 20.2, and 30.7% graphene, polyacrylonitrile nanofibers, polyurethane nanofibers, and polyamide 6 nanofibers were compared in terms of extraction recovery and cleanup efficiency with both the commercial restricted access media sorbent RP-18 ADS (RAM) and molecularly imprinted polymers (MIP). The MIP sorbent was a mixture prepared from commercial Affinimip selective for ochratoxin A and zearalenone, and home-made MIP for citrinin (1:1:1). The polymer fibers and the MIP mixture were filled in a cartridge similar in size to the commercial RAM column and the clean-up step as well as the subsequent chromatographic separation were optimized. The HPLC separation of mycotoxins was carried out using Kinetex Biphenyl (150 × 4.6 mm, core–shell particle size 5 µm) analytical column followed by fluorescence detection. The excitation and emission wavelengths were set at 335/497 nm for citrinin and ochratoxin A, and 270/458 nm for zearalenone, respectively. The mobile phase used for the gradient elution of the mycotoxins consisted of 0.5% aqueous formic acid and acetonitrile. The zearalenone contaminations found in plant-based beverages ranged from 9.5 to 14.6 μg L−1 and were within the tolerable limit defined by the European Union.

Ceramic Open Cell Foams Featuring Plasmonic Hybrid Metal Nanoparticles for In Situ SERS Monitoring of Catalytic Reactions

AbstractThis work presents porous zirconia‐toughened alumina ceramics functionalized with Au@Pd/Au@Pt core–shell nanoparticle (NP) for in situ monitoring of catalytic reactions via surface‐enhanced Raman scattering (SERS) which is augmented by the open cell foam structure of the ceramic support. In this respect, the porous ceramic enables efficient light trapping and propagation onto the coated surface, which provides good accessibility of the catalyst, while the core–shell particles are equipped with a catalytically active shell and a plasmonic core which enables SERS sensing. The metallic hybrid core–shell NPs are synthesized by the Au‐seed mediated method and colloidally deposited onto the open porous ceramic matrix prepared via the polymer replica method. The Au@Pt NP functionalized porous ceramic show a Raman enhancement factor up to 106, which is significantly higher than that of non‐porous samples. In situ reaction monitoring via SERS is demonstrated by the Pt‐catalyzed reduction of 4‐nitrothiophenol to 4‐aminothiophenol, showing high specificity for analysis of reactants and products. This multifunctional material concept featuring ceramics‐augmented SERS and catalytic activity could be extended beyond real‐time, sensitive reaction monitoring toward high temperature reactions, photothermal catalysis, bioprocessing and ‐sensing, green energy conversion, and related applications.

Sodium alginate/chitosan-coated TiO2NPs hybrid fiber with photocatalytic self-cleaning property, UV resistance and enhanced tensile strength

SA/CS-coated TiO2NPs hybrid fibers with photocatalytic self-cleaning properties, UV resistance and enhanced tensile strength were successfully prepared by adding CS-coated TiO2NPs to SA matrix. The FTIR and TEM results demonstrate the successful preparation of CS-coated TiO2NPs core-shell structured composite particles. SEM and Tyndall effect results showed that the core-shell particles were uniformly dispersed in the SA matrix. When the content of Core-shell particles increased from 0.1 to 0.3 wt%, the tensile strength of SA/CS-coated TiO2NPs hybrid fibers increased from 26.89 to 64.45 % compared with SA/TiO2NPs hybrid fibers. The SA/CS-coated TiO2NPs hybrid fiber (0.3 wt%) exhibits excellent photocatalytic degradation performance, achieving a 90 % degradation rate for the RhB solution. And the fibers also exhibit outstanding photocatalytic degradation performance towards various dyes and stains commonly encountered in daily life, including methyl orange, malachite green, Congo red, coffee and mulberry juice. The UV transmittance of the SA/CS-coated TiO2NPs hybrid fibers decreased significantly from 90 % to 75 % with the increase in core-shell particle addition, and correspondingly, the UV absorption capacity increased. The SA/CS-coated TiO2NPs hybrid fibers prepared lay the groundwork for potential applications in various fields, including textiles, automotive engineering, electronics and medicine.

Mesoporous colloidal silica cubes with catalytically active cores

Preparation methods of cubic core-shell particles with specific functionality are limited. Here we demonstrate the possibility to transform cuprous oxide cubes coated with mesoporous silica into functional core-shell particles, while retaining their cubic shape. Cuprous oxide nanocubes are coated with mesoporous silica using cetyltrimethylammonium bromide as a template, after which the cuprous oxide core is transformed using liquid phase calcination and galvanic replacement. Nitrogen physisorption and electron microscopy confirm that mesoporous silica coatings are obtained with tuneable thickness. The successful transformation of cuprous oxide into gold and silver is assessed via UV–VIS spectroscopy and energy dispersive X-ray spectroscopy. Particles with a silver core and a cubic mesoporous silica shell are demonstrated to be catalytically active in the degradation of the dye Congo red.Graphical abstract

Functional Ligand-Enabled Particle Assembly for Bio-Nano Interactions.

ConspectusFunctional ligands consist of a wide range of small or large molecules that exhibit a spectrum of physical, chemical, and biological properties. A suite of small molecules (e.g., peptides) or macromolecular ligands (e.g., antibodies and polymers) have been conjugated to particle surfaces for specific applications. However, postfunctionalization of ligands often presents challenges in controlling the surface density and may require the chemical modification of ligands. As an alternative option to postfunctionalization, our work has focused on using functional ligands as building blocks to assemble particles while maintaining their intrinsic (functional) properties. Through self-assembly or template-mediated assembly strategies, we have developed a range of protein-, peptide-, DNA-, polyphenol-, glycogen-, and polymer-based particles. This Account discusses the assembly of such nanoengineered particles, which includes self-assembled nanoparticles, hollow capsules, replica particles, and core-shell particles, according to three categories of functional ligands (i.e., small molecules, polymers, and biomacromolecules) that are used as building blocks for their formation. We discuss a range of covalent and noncovalent interactions among ligand molecules that have been explored to facilitate the assembly of particles. The physicochemical properties of the particles, including size, shape, surface charge, permeability, stability, thickness, stiffness, and stimuli-responsiveness, can be readily controlled by varying the ligand building block or by tuning the assembly method. By selecting specific ligands as building blocks, the bio-nano interactions (i.e., stealth, targeting, and cell trafficking) can also be modulated. For instance, particles composed mainly of low-fouling polymers (i.e., poly(ethylene glycol)) exhibit an extended blood circulation time (half-life > 12 h), while antibody-based nanoparticles demonstrate that a trade-off between stealth and targeting may be required when designing targeting nanoparticle systems. Small molecular ligands, such as polyphenols, have been used as building blocks for particle assembly as they can interact with various biomacromolecules through multiple noncovalent interactions, retain the function of biomacromolecules within the assembly, enable pH-responsive disassembly when coordinating with metal ions, and facilitate endosomal escape of nanoparticles. A perspective is provided on the current challenges associated with the clinical translation of ligand-based nanoparticles. This Account is also expected to serve as a reference to guide the fundamental research and development of functional particle systems assembled from various ligands for diverse applications.

Fabrication of Assembled FeS2 Nanosheet and Application for High-Performance Supercapacitor Electrodes.

To overcome the low-energy-density limitation of supercapacitors, we aimed to achieve a material with a high specific capacitance by manipulating the nanostructure of FeS2, which comprises the most abundant and affordable elements. In this study, nanosheet-assembled FeS2 (NSA-FeS2) was fabricated using a novel method. Sub-micron droplets of sulfur particles stabilized with polyvinylpyrrolidone were formed in silicone oil medium, and Fe(CO)5 was absorbed and reacted on the surface to form core-shell particles, ES/[Fe], with a sulfur core and an iron-containing outer shell. The high temperature treatment of ES/[Fe] produced NSA-FeS2, in which pyrite FeS2 nanosheets grew and were partially interconnected. In a three-electrode system, the as-prepared NSA-FeS2 and NSA-FeS2/polyaniline (PANI) composites exhibited specific capacitances of 763 and 976 Fg-1, respectively, at a current density of 0.5 Ag-1, with corresponding capacitance retentions of 93 and 96% after 3000 charge-discharge cycles. The capacitance retention of the NSA-FeS2/PANI composites was 49% when the current density was increased from 0.5 to 5 Ag-1. Notably, the obtained specific capacitances exhibited the highest values in pure FeS2 and FeS2-based composites, indicating the significant potential for the utilization of iron sulfide in pseudocapacitive electrode materials.

Magnetorheological study of core−shell structured carbonyl iron/2-D graphene oxide microparticles suspensions with improved sedimentation stability

This study aims to assess the rheological and stabilization characteristics of magnetorheological (MR) suspension by dispersing core–shell particles (graphene oxide (GO) as a shell and carbonyl iron (CI) as a core). A simple wet stirring technique was utilized to achieve the grafting of bare carbonyl particles (CIPs) with para-aminobenzoic acid (g-CIPs), and graphene oxide with concentrations of 1 and 2 wt%. The morphological, magnetization and elemental characteristics of prepared core–shell particles were analyzed by Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS), powder X-Ray diffraction (XRD), Raman Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The encapsulation of grafted carbonyl iron particles with graphene oxide enhanced the surface roughness, while the structure of carbonyl iron particles retained its spherical shape. The presence of core–shell particles increased the affinity between the suspended particles and carrier oil, leading to better stability against sedimentation. The stability of prepared MR suspensions was examined by the visualization technique in which graphene oxide encapsulated carbonyl iron particles (GO@g-CIPs) showed remarkable improvement in sedimentation stability. The MR suspension is based on 1 wt% graphene oxide coated carbonyl iron particles (GO@g-CIPs-1) exhibits a sedimentation ratio of 44%, which is higher than that of the MR suspension based on 2 wt% graphene oxide coated carbonyl iron particles (GO@g-CIPs-2) (32%) and the MR suspension containing bare CIPs (20%). Finally, the magnetorheological study was carried out using a rotational rheometer. GO@g-CI based MR suspensions demonstrated a promising magnetorheological performance and identical MR characteristics, with varying yield stress.

A Novel Surface Modification on Core-Shell Yellow Particles for Electrophoretic Display.

This paper reports the synthesis of yellow-charged particles with a core-shell structure by modifying yellow pigment 181 particles using an ionic liquid under the sol-gel and grafting methods. The core-shell particles were characterized using various methods, including energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, colorimetry, thermogravimetric analysis, and others. The changes in zeta potential and particle size before and after modification were also measured. The results demonstrate that the surface of the PY181 particles was successfully coated with SiO2 microspheres, resulting in weak color change but increased brightness. The shell layer also caused an increase in the particle size. Moreover, the modified yellow particles exhibited apparent electrophoretic response, indicating improved electrophoretic properties. The core-shell structure significantly enhanced the performance of organic yellow pigment PY181, making this method a practical modification approach. This method provides a novel way of improving the electrophoretic performance of color pigment particles that are challenging to directly connect with an ionic liquid, leading to the improved electrophoretic mobility of pigment particles. It is suitable for the surface modification of various pigment particles.

PROPERTIES OF NANOSTRUCTURED COMPOSITES OF POLY(VINYLIDENE FLUORIDE) WITH DOPED POLY(3-METHYLTHIOPHENE)

The combination of properties of intrinsically conducting polymers (ICPs) and functional nanostructured template materials opens up prospects for their use in various fields, ranging from bioelectronics to sensors and energy conversion. Successful combinations solve one of the important drawbacks of many ICPs, created by their insolubility and infusibility, and help to achieve their full potential in thermally processable materials. When developing such hybrid materials, it is necessary to take into account the sensitivity of ICP properties to interphase interactions due to extended π-conjugation in these polymers. However, this aspect of ICP-based nanocomposites has not been sufficiently studied yet. In this paper we investigate the effect of template submicron poly(vinylidene fluoride) (PVDF) particles and the nature of the dopant on properties of poly(3-methylthiophene) (P3MT) precipitated as the shell at the PVDF core surface in the course of the 3MT oxidative polymerization. For this purpose, we compare the properties of P3MT phase of the composites with the properties of the neat P3MT doped with dodecylbenzenesulfonate (DBS), perfluorooctanoate (PFO) and chloride anions. In the formed composite core-shell particles the P3MT is in the form of asymmetric nanoparticles which are localized almost exclusively at the surface of PVDF particles. According to the conjugation length, neat polymers form the following series: P3MT-Cl > P3MT-DBS > P3MT-PFO as evidenced by the IR spectral analysis. In their composites the conjugation length of P3MT doped with Cl- does not change noticeably, while for the DBS and PFO anions cases it increases and for the DBS case it exceeds that of Cl- case. X-ray phase analysis showed an increase in the degree of crystallinity of P3MT-Cl and P3MT-DBS phases in the composition of composites by 1.4 and 1.3 times relative to the corresponding values for the neat doped P3MTs. Such an increase can be caused by the influence of the local electric field of the dipoles of the electroactive part of the crystalline phase of PVDF (β- and γ-phase) on the spatial arrangement of charged P3MT macromolecules formed on the surface of PVDF. Thermogravimetric studies show an increase in the thermal stability of the doped P3MT phase of nanocomposites while conductivity measurements reveal a significant effect of the nature of the dopant anion.

Simple Preparation Method of Silica Core–Shell Spheres for HPLC in Undergraduate Chemistry

High-performance liquid chromatography (HPLC) experiments are an important part of the undergraduate analytical instrumentation laboratory courses and usually use commercial C18 silica-packed reversed-phase columns. In this experiment, a simple method of preparing SiO2 core–shell packed columns was developed to enable students to master the whole process of HPLC experiment from stationary phase preparation and column packing to separation experiments, just as they do for gas chromatography. Nonporous SiO2 particles with a particle size of approximately 2.2 μm were prepared by a three-step dilution reaction using the sol–gel method. The product yield was 92.1%. Monodisperse and spherical SiO2 core–shell particles (SiO2@dSiO2) with a particle size of about 2.4 μm were prepared by a one-step hydrothermal method using the prepared SiO2 spheres as the core. The product yield was 83.3%. The prepared SiO2@dSiO2 particles were derivatized with n-octadecyldimethylchlorosilane and then packed into a stainless steel chromatography column. A high column efficiency of 83,188 theoretical plates per meter was obtained for fluorene in reversed-phase mode for the separation of a mixture of polycyclic aromatic hydrocarbons. The column efficiency obtained with this method is the same as that of a commercial column packed with fully porous particles of the same particle size. The SiO2 core–shell stationary phase preparation method developed in this experiment has the advantages of simple process, high yield, and good repeatability. The experiment can be designed to be completed over a period of 1–3 weeks. Inorganic material synthesis is another important aspect of this experiment.

Tunable Red Clusteroluminescence Polymers Prepared by a Simple Heating Process

Clusteroluminescence (CL) has drawn much attention in recent years. However, the design of red emission clusteroluminogens (CLgens) with tunable CL is still in its infancy. Herein, we report a simple heating process to prepare red emission poly(maleic anhydride-alt-vinyl acetate) (PMV) derivatives with a tunable maximum emission wavelength between 620 and 675 nm. First, heating above the glass transition temperature (Tg) would promote the movement of polymer chains and facilitate the formation of clusters in both solid and solution states. Then, heating beyond the decomposition temperature at which vinyl acetate converts into C═C is favorable to the formation of new clusters and large through-space conjugation among subgroups in polymer chains. Their synergistic effects realize the adjustable emission wavelength and higher quantum yield of polymers. Additionally, low-cost and eco-friendly core-shell PMV particles are prepared as agricultural light conversion agents and exhibit great compatibility with polyethylene.

Molecular insight into toughening induced by core-shell structure formation in starch-blended bioplastic composites

Binary and ternary blends with poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and thermoplastic starch (TPS) were prepared by a melt process to produce biodegradable biomass plastics with both economical and good mechanical properties. The mechanical and structural properties of each blend were evaluated. Molecular dynamics (MD) simulations were also conducted to examine the mechanisms underlying the mechanical and structural properties. PLA/PBS/TPS blends showed improved mechanical properties compared with PLA/TPS blends. The PLA/PBS/TPS blends with a TPS ratio of 25–40 wt% showed higher impact strength than PLA/PBS blends. Morphology observations showed that in the PLA/PBS/TPS blends, a structure similar to that of core-shell particles with TPS as the embedding phase and PBS as the coating phase was formed, and that the trends in morphology and impact strength changes were consistent. The MD simulations suggested that PBS and TPS tightly adhered to each other in a stable structure at a specific intermolecular distance. From these results, it is clear that PLA/PBS/TPS blends are toughened by the formation of a core-shell structure in which the TPS core and the PBS shell adhered well together and stress concentration and energy absorption occurred in the vicinity of the core-shell structure.

Bio-inspired hydrophobic copper stearate coating to reduce the moisture absorption of fine-grained ammonium perchlorate and improve safety and thermal decomposition performance

Inspired by the superhydrophobic phenomenon in nature, multifunctional fine-grained ammonium perchlorate (F-AP)@copper stearate (CS) core-shell structure composite particles were designed by the in-situ liquid deposition method. Scanning electron microscopy (SEM) characterization proved that raw AP was refined, and a series of in-depth characterizations proved that the core-shell structure of F-AP@CS was prepared. Due to the core-shell F-AP@CS bionic hydrophobic structure and low surface energy, when the CS content is 5%, the moisture absorption rate was reduced from 0.54% to 0.03% within 72 h, and the water contact angle was increased to 126.6°. At room temperature, the safety performance of F-AP is effectively improved because of the barrier effect and melting heat absorption of the CS shell, the impact sensitivity (H50) of F-AP@CS (wt = 5%) was increased from 27.2 cm to 54.2 cm, and the friction sensitivity was reduced from 96% to 0%. As the temperature rises, CS will decompose into CuO with extremely high catalytic activity at 267 °C, the high temperature decomposition peak of F-AP@CS (wt = 5%) was advanced from 423.3 °C to about 305.9 °C, and speculate the mechanism of CS catalyzing the decomposition of AP.