Al NPs Research Articles

Chinese yam polysaccharide-loaded aluminium hydroxide nanoparticles used as vaccine adjuvant to induce potent humoral and cellular immune responses

Due to their safety and efficacy, aluminium salts (Alum) are considered the most important adjuvants in human vaccines. However, Alum adjuvants are unable to elicit a cellular immune response, which is vital for the prevention of various chronic infectious diseases and cancers. Herein, we isolated and purified a water-soluble polysaccharide from Chinese yam, named CYP, which was primarily composed of →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, and α-D-Glcp-(1→. Meanwhile, we prepared aluminium hydroxide nanoparticles (Al NPs) with a nanometer-scale size and thin stick-like shape. Being an immunostimulant, the CYP was then loaded onto the Al NPs to obtain a novel adjuvant delivery system (CYP-Al NPs) that enhances the immunostimulatory activity of CYP. Our findings showed that the CYP-Al NPs facilitated macrophages activation and promoted the antigen uptake by macrophages. The in vivo experiment showed that the CYP-Al NPs, as the adjuvant to ovalbumin, promoted the activation of dendritic cells and germinal center B cells in draining lymph nodes, induced a durable and strong antibody response, especially the Th1-type IgG2a antibody response, and improved the cytotoxic T lymphocytes response. These results demonstrated that the CYP-Al NPs could generate robust humoral and cellular responses, and has the great potential to serve as an adjuvant delivery system.

Bio-effects of present of AL NPs in Different Vaccines on Hematology Analysis of Rabbit’s In-Vivo Study

Bio-effects of present of AL NPs in Different Vaccines on Hematology Analysis of Rabbit’s In-Vivo Study

Study on the combustion characteristics and reaction mechanism of aluminum/alcohol-based nanofluid fuel

Enhancing the volumetric energy density of fuels is a crucial approach in the exploration of efficient energy sources. As a commonly used high-energy additive, Aluminum nanoparticles (Al NPs) holds broad application prospects. This study delves into the effects of Al NPs on the combustion characteristics of methanol and ethanol fuels through in-depth analysis of single droplet combustion and spray combustion experiments involving alcohol-based nanofluid fuels. The experiments revealed that adding Al NPs significantly enhances fuel combustion efficiency, shortening both the combustion life and ignition delay time. Spray combustion tests demonstrated that adding 2 wt% Al NPs increased the maximum and average flame propagation speeds of ethanol fuel spray by 48.93 % and 47.94 %, respectively, while the maximum explosion pressure rose from 0.66MPa to 0.83MPa, with a reduced time to reach peak explosion pressure by 106ms. Based on the SEM and XRD characterization results of the combustion residues and the analysis of flame morphology, a physical model of the alcohol-based nanofluid fuel spray combustion flame was established. Numerical simulations of the gas-phase kinetics model showed that the generation rates of radicals such as H, O, and OH were significantly increased with the addition of Al NPs, intensifying the combustion reaction. The findings provide a theoretical basis for future fuel design and combustion performance optimization.

“Fireworks” ignition and combustion of metal nanoparticles: Based on the rapid conversion and transmission of microwave energy by energetic ionic liquids

The metal nanoparticles (MNPs) are widely used to improve the output performance of various explosives and propellants, which ignition is an important link for the energy release of fuel. The microwaves have been recognized as a safer and smart ignition method. However, it is difficult to achieve rapid ignition of MNPs under microwave radiation due to the low heating rate. The ADN energetic ionic liquids could efficiently absorb microwaves owing to excellent polarity. This work proposes a method of fast “fireworks” ignition and combustion of MNPs under microwave radiation, by employing ADN as the “central hub” for microwave energy conversion. The dispersion of Al and Ti NPs in ADN endowed the solution with nanofluid properties and significantly improved the thermal conductivity. The solution boiled violently under microwave radiation, causing the temperature of MNPs to rise continuously. Meanwhile, the acidic components produced by ADN pyrolysis destroyed the oxide shell of MNPs, further accelerating the ignition process. The ignition phenomenon of Al and Ti NPs were different due to distinct microwave absorption properties and ignition temperature. When the expanding liquid film broken, the shock wave blew the Al NPs into the air to realize the “fireworks” ignition and combustion. The Ti NPs was ignited in the solution, which further ignited the ADN solution, allowing the system for controllable ignition and combustion. The “fireworks” ignition and combustion performance of MNPs could be modulated by the input microwave power. In summary, the new ignition and combustion method of MNPs will have a profound impact on the design of ignition sequence, the improvement of microwave energy utilization and the expansion of the application of ADN-based liquid propellants.

Mechanistic study on the modification of Al NPs by PVDF with different interfacial binding methods to suppress agglomeration and promote combustion

The modification of aluminum nanoparticles (Al NPs) by polyvinylidene fluoride (PVDF) can significantly enhance their reaction characteristics and reduce combustion agglomeration. However, the impact and underlying mechanisms of changes in interfacial binding methods between them on the reaction process remain unclear. In this study, the oxidation and combustion processes, as well as the agglomeration behavior of Al NPs under three different interfacial binding methods (mixing, with oxygenation layer coating, and without oxygenation layer coating) between Al NPs and PVDF were investigated by utilizing ReaxFF molecular dynamics simulations, density functional theory calculations, and ignition experiments. The results indicate that changes in the interfacial binding method significantly affect the oxidation behavior of Al NPs, and PVDF molecules exhibit different decomposition pathways on the surfaces of Al and Al2O3. During the combustion stage, different interfacial binding methods determine distinct reaction modes between Al NPs and PVDF. Based on these findings, a reaction mechanism for Al NPs and PVDF is proposed. This study addresses the gap in the field of the impact of interfacial binding methods on the reaction processes between Al NPs and PVDF, laying a theoretical foundation for future research and providing guidance for the practical application of Al-based modified fuels.

Preparation of Al@FTCS/P(VDF-HFP) Composite Energetic Materials and Their Reaction Properties.

Strengthening the interfacial contact between the reactive components effectively boosts the energy release of energetic materials. In this study, we aimed to create a close-knit interfacial contact condition between aluminum nanoparticles (Al NPs) and Polyvinylidene fluoride-hexafluoropropylene (P(VDF-HFP)) through hydrolytic adsorption and assembling 1H, 1H, 2H, 2H-Perfluorododecyltrichlorosilane (FTCS) on the surface of Al NPs. Leveraging hydrogen bonding between -CF and -CH and the interaction between C-F⋯F-C groups, the adsorbed FTCS directly leads to the growth of the P(VDF-HFP) coating layer around the treated Al NPs, yielding Al@FTCS/P(VDF-HFP) energetic composites. In comparison with the ultrasonically processed Al/P(VDF-HFP) mixture, thermal analysis reveals that Al@FTCS/P(VDF-HFP) exhibits a 57 °C lower reaction onset temperature and a 1646 J/g increase in heat release. Associated combustion tests demonstrate a 52% shorter ignition delay, 62% shorter combustion time, and a 288% faster pressurization rate. These improvements in energetic characteristics stem from the reactivity activation of FTCS towards Al NPs by the etching effect to the surface Al2O3. Moreover, enhanced interfacial contact facilitated by the FTCS-directed growth of P(VDF-HFP) around Al NPs further accelerates the whole reaction process.

Perfluorotetradecanoic acid-directed precipitation of P(VDF-HFP) around nano-Al for the improved ignition and combustion characteristics

In this study, the self-assembly method is used to modify Al nanoparticles (Al NPs) with perfluorotetradecanoic acid (PFTD) to obtain Al@PFTD. Based on the C–F…F–C interaction and the hydrogen bond between –CF and –CH, the adsorbed PFTD is used to direct the precipitation of P(VDF-HFP) around modified Al NPs to obtain Al@PFTD@P(VDF-HFP) composite energetic materials. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy are used to characterize the prepared samples, which prove a successful preparation process. The prepared Al@PFTD@P(VDF-HFP) is compared with physically mixed Al/P(VDF-HFP) counterparts by thermal analysis, electric ignition and constant-volume combustion tests. Thermal analysis results show that the reaction onset temperature of Al@PFTD@P(VDF-HFP) is 20 °C lower while its heat release is 135% higher. Electric ignition and constant-volume combustion tests show that the ignition delay, combustion time and pressurization rate are 50% shorter, 50% shorter and 40% faster, respectively. The improved energetic performance is mainly due to PFTD-directed precipitation of P(VDF-HFP) around Al NPs. Moreover, the fluorine-containing PFTD also contributes positively to energy density and reactivity through the pre-ignition reaction.

Metal-based nanoparticles: basics, types, fabrications and their electronic applications

Abstract Nanoparticles below 100 nm have sparked immense interest for their unique physical and chemical properties, separate from bulk materials. These particles have versatile applications in electronics, magnetism, optoelectronics, and electricity. This article overviews ongoing research on nanoparticle-based electronic devices and explores anticipated advancements. In electronics, nanoparticles are essential components for enhanced performance and functionality, promising breakthroughs in computing, telecommunications, and sensing. This work explores the groundbreaking potential of metal-based nanoparticles, such as ZnO NPs, Cu NPs, Al NPs, and Fe NPs, in various electronic device applications. It investigates different synthetic methods, including bottom–up, sol–gel, co-precipitation, hydrothermal, CVD, and green/biological method to enhance the effectiveness of these nanoparticles. The study briefly examines the efficiency of these nanoparticles for electronic device applications, and it extends their potential applications to areas such as data storage, sensors, protective coatings, energy storage, chemical industries, water treatment, fertilizers, and defense. Challenges include precise control of nanoparticle shape and arrangement, which researchers address to design new materials with controlled properties. The present work discusses the anticipated and emerging applications of nanoparticles, emphasizing their unique physical and chemical properties compared to bulk materials. Ongoing research explores their full potential, while manipulation techniques open doors to novel materials. The progress made underscores the immense possibilities of nanoparticle-based electronics.

Enhanced energy delivery of direct-write fabricated reactive materials with energetic graphene oxide

Aluminum (Al) based reactive materials are of interest as their addition can significantly increase the energy density of energetic composites such as solid propellants. In this study, we employed graphene oxide (GO) as an energetic gas generator to increase the ignitability of Al and promote the flame propagation of Al/CuO thermite composites. Compared to the pristine Al/CuO composite, 2.5 wt % addition of GO releases gas and heat upon disproportionation, resulting in a 2X higher burn rate and heat flux. Though both GO and reduced graphene oxide (rGO) addition can reduce the agglomeration size of Al NPs by 2X, GO is more energetic with heat and gas release at low temperature, granting it the ability to increase the ignitability of Al NPs and promote the energy delivery of Al/CuO composite. This study provides a simple way to increase the energy delivery rate of reactive materials by adding a small percentage of functionalized carbon nanomaterials.

Thermal cracking performance of Al-nanoparticle-containing nanofluids

Endothermic hydrocarbon fuels containing energetic nanoparticles, which combine high-energy–density and endothermic capability, are promising for improving the flight performance of hypersonic vehicles. Here, the feasibility of nanofluid fuels as energetic endothermic fuel is studied. Aluminum nanoparticles (Al NPs)-containing nanofluid fuels were prepared by dispersing 0.1 wt% and 0.5 wt% Al NPs into JP-10, decahydronaphthalene (DHN) and methylcyclohexane (MCH), respectively. Characterizations of nanofluid fuels confirm the addition of Al NPs improves the density and combustion performance of the hydrocarbon fuels. The cracking performance of three fuels with Al NPs added is slightly inhibited in the order of DHN > MCH > JP-10. Cracking conversion (and heat sink) of JP-10, DHN and MCH containing 0.5 wt% Al NPs decrease by 3.0 %, 18.8 % and 14.1 % (and 0.04, 0.09 and 0.05 MJ/kg), respectively. JP-10 is the least affected by Al NPs. Meanwhile, Al NPs are observed to slightly increase the amount of coking during cracking, and the non-uniformly dispersed Al can be found in the coke deposition. This work indicates the potential application of energetic nanofluids to serve as endothermic fuels, and provides the method for the further development of high-energy–density endothermic fuels.

Mechanistic study of the influence of aluminum nanoparticles on the pressure sensitivity of 1,3,5-trinitro1,3,5-triazinane (RDX) thermal decomposition

The incorporation of Al nanoparticles (Al NPs) into 1,3,5-trinitro1,3,5-triazinane (RDX) can catalyze its thermal decomposition and reduce the pressure exponent (n) of solid propellants. However, the underlying reaction mechanism at a deeper level remains unclear. In this study, the reaction processes of Al NPs catalyzing the thermal decomposition of RDX under different initial pressures were investigated by utilizing the ReaxFF molecular dynamics (ReaxFF-MD) simulations combined with DFT calculations, and the influence mechanism of Al NPs on the pressure sensitivity of RDX thermal decomposition was revealed from various perspectives. In the initial stage of the reaction, unlike the nitro group dissociation observed in pure RDX, the incorporation of Al NPs alters the initial decomposition pathway of RDX, making it more easily adsorbed on the surface of Al and enhancing the early-stage decomposition rate. Furthermore, Al NPs exhibit higher catalytic activity in low-pressure systems. In the later stage, because of the massive adsorption of free radicals generated from RDX decomposition on the surface of Al NPs, the decomposition rate of RDX decreases significantly, especially in high-pressure systems. Consequently, Al NPs synergistically reduce the pressure sensitivity of the RDX thermal decomposition from two different perspectives. Compared to traditional experimental research or single RDX simulation studies, this work further explores the interaction between Al and RDX from a microscopic perspective, addressing the gap in the field of the influence mechanisms of Al NPs on the pressure sensitivity of RDX thermal decomposition. It also establishes a theoretical foundation for the practical application of Al@RDX fuels.

Capacitively coupled nonthermal plasma synthesis of aluminum nanocrystals for enhanced yield and size control

Uniform-size, non-native oxide-passivated metallic aluminum nanoparticles (Al NPs) have desirable properties for fuel applications, battery components, plasmonics, and hydrogen catalysis. Nonthermal plasma-assisted synthesis of Al NPs was previously achieved with an inductively coupled plasma (ICP) reactor, but the low production rate and limited tunability of particle size were key barriers to the applications of this material. This work focuses on the application of capacitively coupled plasma (CCP) to achieve improved control over Al NP size and a ten-fold increase in yield. In contrast with many other materials, where NP size is controlled via the gas residence time in the reactor, the Al NP size appeared to depend on the power input to the CCP system. The results indicate that the CCP reactor assembly, with a hydrogen-rich argon/hydrogen plasma, was able to produce Al NPs with diameters that were tunable between 8 and 21 nm at a rate up ∼ 100 mg h−1. X-ray diffraction indicates that a hydrogen-rich environment results in crystalline metal Al particles. The improved synthesis control of the CCP system compared to the ICP system is interpreted in terms of the CCP’s lower plasma density, as determined by double Langmuir probe measurements, leading to reduced NP heating in the CCP that is more amenable to NP nucleation and growth.

Ultrastable Aluminum Nanoparticles with Enhanced Combustion Performance Enabled by a Polydopamine/Polyethyleneimine Nanocoating.

In national defense, aluminum nanoparticles (Al NPs) have better combustion performance than Al microparticles but are easily oxidized during processing, especially in oxidative liquids. Although some protective coatings have been reported, it is still challenging to obtain Al NPs stable in oxidative liquids (e.g., hot liquids) without scarifying combustion performance. Here, we report ultrastable Al NPs with enhanced combustion performance enabled by the crosslinked polydopamine/polyethyleneimine (PDA/PEI) nanocoating merely ∼15 nm in thickness and ∼0.24 wt % in mass. The Al@PDA/PEI NPs are fabricated by one-step rapid graft copolymerization of dopamine and PEI on Al NPs at room temperature. The formation mechanism of the nanocoating is discussed including reactions between dopamine and PEI and interactions of the nanocoating with Al NPs. The Al@PDA/PEI NPs show excellent stability in hot water, and the mechanism is interpreted by molecular dynamics simulation. The PDA/PEI nanocoating can also enhance the combustion heat and burning rate of Al NPs.

Biofunctionalization of HMX with Peptides via Polydopamine Crosslinking for Assembling an HMX@Al@CuO Nanoenergetic Composite.

Biological approaches for the synthesis of a hybrid explosive-nanothermite energetic composite have attracted greater scientific attention because of their advantages, including their moderate reactions and the absence of secondary pollution. In this study, a simple technique was developed to fabricate a hybrid explosive-nanothermite energetic composite based on a peptide and a mussel-inspired surface modification. Polydopamine (PDA) was easily imprinted onto the HMX, where it maintained its reactivity and was capable of reacting with a specific peptide used to introduce Al and CuO NPs to the surface of the HMX via specific recognition. The hybrid explosive-nanothermite energetic composites were characterized using differential scanning calorimetry (TG-DSC), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy(XPS), and a fluorescence microscope. A thermal analysis was utilized to investigate the energy-release properties of the materials. The HMX@Al@CuO, which benefitted from an enhanced interfacial contact in comparison with the physically mixed sample (HMX-Al-CuO), demonstrated a 41% lower HMX activation energy.

Engineered Surface Chemistry and Enhanced Energetic Performance of Aluminum Nanoparticles by Nonthermal Hydrogen Plasma Treatment.

Extracting the maximum chemical energy from aluminum nanoparticles (Al NPs) during oxidation is essential for their use in energetic applications. However, the shell of native Al2O3 limits the release of chemical energy by acting as a diffusion barrier and dead weight. Engineering the surface properties of Al NPs by modifying their shell chemistry can reduce the inhibiting effects of the oxide shell on the rate and heat release of oxidation. Here, we employ nonthermal hydrogen plasma at high power and a short time to alter the shell chemistry by doping it with Al-H, as examined and confirmed by HRTEM, FTIR, and XPS. Thermal analysis (TGA/DSC) shows that Al NPs with modified surfaces exhibit augmented oxidation and heat release (33% higher than those of untreated Al NPs). The results demonstrate the promising effect of nonthermal hydrogen plasma in engineering the shell chemistry of Al NPs to improve their overall energetic performance during oxidation.

Plasmonic-enhanced efficiency of AlGaN-based deep ultraviolet LED by graphene/Al nanoparticles/graphene hybrid structure.

The AlGaN-based deep ultraviolet light-emitting diode (DUV LED) has advantages of environmentally friendly materials, tunable emission wavelength, and easy miniaturization. However, the light extraction efficiency (LEE) of an AlGaN-based DUV LED is low, which hinders its applications. Here, we design a graphene/Al nanoparticles/graphene (Gra/Al NPs/Gra) hybrid plasmonic structure, where the strong resonant coupling of local surface plasmons (LSPs) induces a 2.9-times enhancement for the LEE of the DUV LED according to the photoluminescence (PL). The dewetting of Al NPs on a graphene layer by annealing is optimized, resulting in better formation and uniform distribution. The near-field coupling of Gra/Al NPs/Gra is enhanced via charge transfer among graphene and Al NPs. In addition, the skin depth increment results in more excitons being coupled out of multiple quantum wells (MQWs). An enhanced mechanism is proposed, revealing that the Gra/metal NPs/Gra offers a reliable strategy for improving the optoelectronic device performance, which might trigger the advances of LEDs and lasers with high brightness and power density.

Anticorrosion and Antibacterial Properties of Al NP–Epoxy Nanocomposite Coating on Grey Cast Iron

In this study, different concentrations of aluminium nanoparticles (Al NP) were incorporated into epoxy resin and epoxy paint. Here, we present a detailed systematic study of different methods of incorporating inorganic nanoparticles into epoxy coating. This work aims to obtain an epoxy coating with anticorrosion and antibacterial properties. The physical properties of coatings such as thickness, hardness, colour, and adhesion did not change with the addition of nanoparticles. According to the SEM and EDS analyses, the distribution effect of Al NPs in epoxy coating was better with ultrasonic homogenisation than with mechanical stirring. The EIS and SECM measurements were used to investigate corrosion resistance. The coating with 1.0 wt.% Al NP showed the best physical and chemical properties. SECM examination indicated that nanoparticles in epoxy resin increase the protection efficiency by 25.75% and in the epoxy paint by 40.89%. The results also showed the antibacterial activity of aluminium nanoparticles by inhibiting the growth of biofilm-forming bacteria such as P. aeruginosa and B. subtilis.

Oxidation mechanism of perfluorooctanoic acid-functionalized aluminum metastable intermolecular composites regulated by Preignition reactions interface fuel-oxidizer ratio

PFOA-functionalized Al Metastable Intermolecular Composites (MICs) refer to the system using aluminum nanoparticles as fuel and PFOA as oxidant. Aluminum is the most widely used metal fuel in energetic materials. Al NPs are widely used because they are relatively cheap, easily accessible, nontoxic, excellent in thermodynamic performance. Fluorine has higher density and stronger oxidation capacity than oxygen element. PFOA has a high fluorine content (68.8%). PFOA-functionalized Al MICs mixed the high calorific value of aluminum and oxidizing fluorine in nano-sized. In this paper, PFOA-functionalized Al MICs with different PIR interface fuel-oxidizer ratios were prepared by electrostatic spray. The microstructure of the MICs was characterized by TEM. PFOA is uniformly coated on the Al NPs. The composition of MIC system was analyzed by FTIR and XRD. The combustion performance of MICs was tested by laser ignition, and the decomposition mechanism of PFOA-functionalized Al MICs was studied by DSC-TG. Results show that the exothermic process and activation energy of MICs are affected by the Preignition reactions (PIR) interface fuel-oxidizer ratios. The ignition and combustion processes of MICs and pressurization rate increase with the increase of oxidizer, and the burning rate decreases with the increase of oxidizer.

Effect of Green-biosynthesis Aluminum Nanoparticles (Al NPs) on Salmonella enterica Isolated from Baghdad City

This study is aimed to Green-synthesize and characterize Al NPs from Clove (Syzygium aromaticumL.) buds plant extract and to investigate their effect on isolated and characterized Salmonella enterica growth. S. aromaticum buds aqueous extract was prepared from local market clove, then mixed with Aluminum nitrate Al(NO3)3. 9 H2O, 99.9% in ¼ ratio for green-synthesizing of Al NPs. Color change was a primary confirmation of Al NPs biosynthesis. The biosynthesized nanoparticles were identified and characterized by AFM, SEM, EDX and UV–Visible spectrophotometer. AFM data recorded 122nm particles size and the surface roughness RMs) of the pure S. aromaticum buds aqueous extract recorded 17.5nm particles size, while the results of Al NPs in the tested sample recorded 21nm particles size with surface roughness RMs about 2.35nm. SEM images revealed the presence of Al NPs with diameters ranged from 33.5-70.4nm with regular spiracles shape particles in the prepared biosynthesized nanoparticle sample. The EDX spectrum analysis showed that the Aluminium weight ratio was 1.75, while it was 50.498 in the Al NPs sample prepared from aqueous extract. UV-Visible spectroscopy data revealed that biosynthesized Al NPs were absorbed at 213nm while Aluminum nitrate was absorbed at 258nm. These results indicate the formation of Al NPs. The antibacterial activity showed that Al NPs exhibited having high antibacterial activity on Salmonella spp. isolates compared to the effect of the control agent (imipenem) in this experiment. We conclude that biosynthesized Al NPs from clove aqueous extract can be exploited as natural antibacterial compounds to inhibit the growth of Salmonella.

Biosafety risk assessment of gold and aluminum nanoparticles in tumor-bearing mice.

To improve the biosafety of the nanodelivery system, this study developed novel monodisperse spherical aluminum nanoparticles (Al NPs) and evaluated their cytotoxicity in vitro and distribution and biotoxicity in vivo. Compared with gold nanoparticles of the same size, Al NPs not only had low cytotoxicity in vitro but also did not cause accumulation in major organs in vivo after intravenous injections. No significant abnormalities were observed in the serum biochemical indices of mice injected with Al NPs. Additionally, no substantial changes occurred in the histopathology of major organs, and no apparent biological toxicity was measured after consecutive injections of Al NPs. These results indicate that Al NPs have a good biological safety and provide a new method for developing low-toxicity nanomedicine.