Surface Energy Of Nanoparticles Research Articles

Wood sponge with photothermal, magnetically driven, and superhydrophobic characteristics for high-viscosity oil–water separation

In this work, naturally degradable porous balsa wood was used as a raw material to prepare a highly elastic wood sponge (WS) substrate using a two-step chemical method and a freeze-drying method. The surface hydrophobic modification of Fe3O4 nanoparticles using the fluorine-free material octadecyltrimethoxysilane (C18TMS) solved the problem of agglomeration caused by the high nanoparticle surface energy. Polydopamine (PDA), hydrophobically modified Fe3O4 (C18TMS/Fe3O4), and low-surface-energy polydimethylsiloxane (PDMS) were sprayed onto WS substrates using a simple spraying method. An environmentally friendly adsorption sponge with photothermal, magnetically driven, and superhydrophobic properties was prepared for the first time using this method. The prepared sponge had a water droplet contact angle of 156.8° and exhibited excellent oil–water separation performances. Due to the addition of PDA and Fe3O4, the modified sponge exhibited excellent photothermal performance, rapidly heating to 63.4°C under a sunlight intensity of 1 kW m−2. The superhydrophobic WS prepared in this experiment provides a more environmentally friendly and low-cost way for high viscosity oil–water separation and targeted removal of oil pollution.

Thermal-driven Dispersion of Bismuth Nanoparticles among Carbon Matrix for Efficient Carbon Dioxide Reduction.

The poor electrocatalytic stability and rapid deactivation of metal electrocatalysts are always present in the electrocatalytic conversion of carbon dioxide (CO2) due to the harsh reduction condition. Herein, we demonstrate the controllable dispersion of ultrafine bismuth nanoparticles among the hollow carbon shell (Bi@C-700-4) simply by a thermal-driven diffusion process. The confinement effect of nitrogen-doped carbon matrix is able to low the surface energy of bismuth nanoparticles against the easy aggregation commonly observed for the thermal treatment. On the basis of the synergistic effect and confinement effect between bismuth nanoparticles and carbon matrix, the highly dispersed active sites render the obviously improved electrocatalytic activity and stability for carbon dioxide reduction into formate. The in-situ experimental observation on the reduction process and theoretical calculations reveal that the incorporation of bismuth nanoparticles with nitrogen-doped carbon matrix would promote the activation of CO2 and the easy formation of key intermediate (*OCHO), thus leading the enhanced electrocatalytic activity, with a Faradaic Efficiency (FE) of formate about 94.8% and the long-time stability. Furthermore, the coupling of an anode for 5-hydroxymethylfurfural oxidation reaction (HMFOR) in solar-driven system renders the high 2,5-furandicarboxylic acid (FDCA) yield of 81.2%, presenting the impressive solar-to-fuel conversion.

Design and tribological performance of graphene nanofluids dispersed by dragging effect of bicomponent gelator

Nanofluids have excellent lubrication and high thermal conductivity. However, the agglomeration and sedimentation produced by the large surface energy of nanoparticles in base liquid threaten the long-term dispersion stability and impact the wide application of nanofluid. In this work, based on the self-assemble behavior and continuous network structure formed by low molecular weight organic gelator, the uniform clusters were formed through regulating the kinetics behavior in the gelling process. The dragging effect was demonstrated by oleic acid - sodium dodecyl sulfate (OA-SDS) bicomponent gelator and graphene oxide (GO) nanosheets. The results showed that GO nanofluids dispersed by OA-SDS were stable for more than 12 months. The well-dispersed GO nanofluid exhibited better anti-friction and anti-wear properties under both immersion and electrostatic minimum quantity lubrication conditions. Moreover, the lower contact angle, surface tension and droplet size of nanofluids after charging improved the wettability on the frictional interface. The GO adsorption film formed on the friction interface protected the tribochemical reaction film of iron oxide and prevented the occurrence of sintering of base oil.

Enzyme-activated apoptotic bodies-encapsulated NSET biomimetic probe for wash-free detection of intracellular pathogen in synovial fluid and monitoring therapy effect of septic arthritis

The survival of Staphylococcus aureus (S. aureus) within host cells leads to recurrences of septic arthritis after conventional treatment, which is a challenging clinical problem. Simple, rapid and sensitive detection of intracellular bacteria in septic arthritis synovial fluid and real-time monitoring of antibiotic efficacy for septic arthritis are important to the management of this disease. Herein, an enzyme-responsive activated nanoparticle surface energy transfer (NSET) biomimetic probe (FP1Au@AB) constructed with a fluorescent polypeptide (FP1)-gold nanoparticle (AuNPs, Au) complex (FP1Au) coated with apoptotic body (AB) was applied to detect intracellular S. aureus in septic arthritis synovial fluid from clinical samples and monitor the treatment of antibiotic of rifampicin (Rif) to septic arthritis in mouse models. The as-prepared NSET bionic probes of FP1Au@AB bears AB coating which makes the probes are of good actively targeting to macrophages, and the probes could be specifically tailored by caspase-1 presented in infected macrophages, resulting fluorescent signal on. Based on the FP1Au@AB probe, the detection of intracellular bacteria in synovial fluid with a low detection limit of 5 (the average number of S. aureus in one host cell) was realized without the need of washing extracellular bacteria beforehand. Additionally, therapy efficacy of septic arthritis in mouse model could be monitored timely based the proposed probe. Moreover, FP1Au@AB probes could be applied to confirm whether the synovial fluid from patients with septic arthritis contained intracellular bacteria or not, which is benefit for the doctor to do the administration. The FP1Au@AB probe-based lighting up analytical method shows great potential for the administration and evaluation of therapy of septic arthritis in clinic.

Thermally stable Pd/CeO2@SiO2 with a core-shell structure for catalytic lean methane combustion.

Noble metal catalysts exhibit high catalytic activity in lean CH4 combustion at low temperatures. However, the high surface energy of noble metal nanoparticles makes them susceptible to deactivation due to migratory-aggregation during the catalytic process. Herein, a core-shell structure with a Pd/CeO2 core and a SiO2 shell (denoted as Pd/CeO2@SiO2) was designed and prepared to enhance the thermal stability for catalytic lean CH4 combustion. A series of characterization methods demonstrated the successful encapsulation of SiO2 and the modified thermal stability. The results of activity tests indicated that Pd/CeO2@SiO2 exhibited the optimal catalytic performance. After seven runs, Pd/CeO2@SiO2 achieved 90% conversion of CH4 at 385 °C compared to Pd/CeO2 at 440 °C. The remarkable catalytic performance was attributed to the synergistic effect of strengthened metal-support interactions and the core-shell structure. On the one hand, the migration and aggregation of Pd nanoparticles were limited due to the protection of the SiO2 shell layer. On the other hand, the SiO2 shell layer further enhanced the interactions between the Pd nanoparticles and CeO2, thus promoting the formation of PdxCe1-xO2-δ solid solutions and active oxygen species, which were beneficial for the improvement of the stability and redox capacity of the catalyst.

Evaluation of the performance of concrete by adding silica nanoparticles and zeolite: A method deviation tolerance study

Researchers have conducted extensive research to develop concretes with improved properties and suitable for harsh environments. The use of nanomaterials to improve the performance of concrete is one of the promising methods for developing optimized concrete. However, the non-uniform distribution of nanoparticles in the concrete matrix limits the reproducibility of the behavior of concretes studied, particularly in industrial or practical environments. The high surface energy of nanoparticles, limitations, and lack of standardization of the production process are responsible for this phenomenon. Addressing this challenge, this study aims to investigate practical implementation conditions of silica nanoparticle and zeolite reinforced concrete. The study examines deviations from the base method, involving synthesized silica nanoparticles via the sol-gel method as the main additive, alongside zeolite as a representative of pozzolanic materials. By examining four parameters influencing the behavior of concrete over a period of 7 days and 180 days, as well as conducting experiments in parallel groups to simulate the practical environment, this study attempted to improve the reproducibility of concrete with silica nanoparticles and zeolites improved behavior. As a result of the study, it was found that the presence of silica and zeolite nanoparticles in 7-day concrete weakens and improves the properties of the concrete by − 10% and + 3%, respectively, for concrete after 7 days, and this effect increases by + 30% and + 93% for concrete after 180 days. This showed that there is a significant correlation between the healing effects of these substances and the amount of time they have been hydrated. Furthermore, concrete containing silica nanoparticles performs 35% better than the control sample. In contrast, concrete containing silica nanoparticles and zeolite provided a 165% improvement over the control sample. Using a correlation analysis of the effects of different parameters on the output performance of 7-day and 180-day concrete, this study presents a more detailed analysis of improved concrete response.

(Invited) Nucleation, Growth and Location Regulation of Heterogeneous Catalysts Synthesized by Atomic Layer Deposition

For supported catalysts, the particle surface or metal-support interface and its vicinity are the main areas providing active sites. In this regard, surface and interface engineering of heterogeneous catalysts is effective and critical for optimizing their catalytic performances. During the formation of active components, the structural uniformity, stability and location of nucleation sites determine the structural and scale uniformity, stability and environmental consistency of active sites, and ultimately determine their catalytic performance. Therefore, the regulation of nucleation, growth and location of active components is the key to precisely regulate the surface and interface structure and properties of supported catalysts. However, traditional preparation methods (such as impregnation method and precipitation method) have limitations in precise regulation of particle size, location and microstructure of catalysts due to the surface heterogeneity of supports and the high surface energy of nanoparticles, which makes it difficult to reliably reveal the structure-activity relationship of the catalyst. Therefore, the development of advanced fabrication methods is of vital significance to realize the nucleation, growth and location regulation of heterogeneous catalysts at atomic level precision. Atomic layer deposition (ALD) is a powerful scientific tool for catalytic research due to its self-limiting, atom-by-atom growth features. However, there is still a lack of rational knowledge of the nucleation and growth mechanism of catalytic particles prepared by ALD, the microscopic mechanism of interface structure modification, and the catalytic reaction mechanism. This is the topic of this lecture, in which we discuss the latest progress made in our group in precisely regulating the microstructure, size and location of ALD-deposited active components by several effective methods including nucleation site engineering, deposition kinetics engineering and template-assisted ALD method, as well as elucidating the nucleation and growth mechanism of ALD-deposited active components by in-situ and operando XAFS characterization based on our designed and built ALD-XAFS device. Through the above works, the nucleation and growth mechanisms of the deposited species and modification species, the microscopic mechanism of interface structure modification, and the influence of the size effect, the interface effect, and the distance effect on the catalytic performance were clarified. The structure-activity relationship was understood at the atomic/molecular level. These works will provide new ideas and scientific basis for the catalyst design and the performance regulation.

Using the surface energy of nanoparticles to produce high-strength concrete

The article considers a method for activating cement hardening processes using nanomaterials due to the magnitude of their surface energy: when injected into concrete, nanoparticles dump it due to the desire to transition to a stable state. Such activity leads to a significant gain in strength, hardness and the production of high-strength concrete. It is shown that such an effect can be achieved by surface impregnation of concrete with sols (colloidal solutions) based on SiO2 nanoparticles. It is advisable to start impregnation from the third day of hardening under normal conditions. At this age, the main heat of the cement's own exothermic hardening reaction has already been released into the environment, and the introduction of additional energy will not cause a shift in equilibrium towards slowing down the hardening processes in accordance with the Le-Chatelier principle. The results of physico-chemical studies of concrete after hardening, explaining this effect, are presented.

Using the Surface Energy of Nanoparticles to Produce High-Strength Concrete

Using the Surface Energy of Nanoparticles to Produce High-Strength Concrete

Reinforcement of TiAl alloy by evenly distributed micron-/nano-Y2O3 particles

TiAl alloy has attracted widespread attention as an alternative material to aero-engine turbine blades. Because the obvious brittleness of TiAl alloy, TiAl alloy reinforced with nano-sized reinforcement is a feasible pathway to improve its mechanical properties due to the nano-sized reinforcement does not easily cause stress concentration and crack initiation while strengthening the alloy matrix. However, since the high specific surface energy and van der waals attraction of nanoparticles, they tend to agglomerate to form unevenly distributed micron-sized particles in alloy melt, which makes it difficult to fabricate TiAl alloys reinforced with nano-sized reinforcements by low-cost casting method. In this work, a TiAl alloy reinforced with evenly distributed micron−/nano-Y2O3 was successfully fabricated by casting method and subsequent heat treatment based on an innovative strategy of stepwise dispersion combined with solid solution-precipitation. Micron-Y2O3 in as-cast TiAl alloy “inherits” the uniform distribution state of Y-rich particles in Al-based master composite; the subsequent heat treatment and furnace cooling process make the nano-Y2O3 uniformly precipitated in the TiAl matrix. Nano-Y2O3 particles (∼ 50 nm) were uniformly distributed in both α2/γ lamellae and lamellar colony boundaries. The ultimate compressive strength and fracture strain of TiAl alloy reinforced with micron−/nano-Y2O3 particles are 1970 MPa and 29.5%, respectively.

ТЕРМОДИНАМИЧЕСКИЙ АНАЛИЗ ПРОЦЕССА ФОРМИРОВАНИЯ НАНОСТРУКТУРНОГО ПОЛИКРИСТАЛЛИЧЕСКОГО МАТЕРИАЛА НА ОСНОВЕ НАНОАЛМАЗОВ, МОДИФИЦИРОВАННЫХ НЕАЛМАЗНЫМ УГЛЕРОДОМ (ЧАСТЬ 1)

The influence of the size of carbon particles on the parameters of the graphite–diamond phase transformation is considered. It is shown that the surface energy of carbon nanoparticles of various shapes (spherical, columnar) makes a significant contribution to their total thermodynamic potential, which leads to a shift in the diamond–graphite equilibrium curve to the low pressure region and an expansion of the diamond phase stability region. At the same time, the change in the chemical potential (Gibbs free energy) during the direct (not catalytic) transition of thin-film graphite-like nanostructures into diamond will be higher than for “massive” graphite, which leads to an increase in the pressure of phase transformation into diamond. To reduce the parameters of diamond formation and obtain nanostructured diamond polycrystals, it is proposed to use nanodiamond particles with a nanometer surface layer of non-diamond (graphitelike) carbon as the starting material. In this case, the nanodiamond surface will influence the transition of a nanometer layer of graphite (graphite-like carbon) into diamond under more favorable thermodynamic parameters.

Formation of corrosion-based ZVMg nanoparticles for reductive degradation of high-level trichloroethylene in aqueous solution

This study discovered that nanosized zero valent magnesium (nZVMg) could be formed during the electrochemical corrosion of microsized ZVMg (mZVMg) in aqueous solution. It is observed that the nZVMg particle sizes were less than 50 nm with the specific surface area of 54.63 m2/g after it was corroded for 96 h (ZVMg96) at the expense of losing about 60 wt% Mg0. However, the XPS characterization indicated the thickness of Mg(OH)2 layer over ZVMg96 being less than 5 nm, accompanied by the faster electron transfer rate but slower corrosion rate than mZVMg. Most importantly, the removal efficiency of 82 % under high-level trichloroethylene (TCE) at 100 mg/L was achieved by ZVMg96 within one hour relative to 48 % by mZVMg. The rate constant normalized by surface area was 3.11 × 10−2 L/m2/h by ZVMg96 due to the high surface energy of nanoparticles. The degradation products were dependent on the initial TCE concentrations, with environmentally friendly and biodegradable degradation products being generated via hydrodechlorination, hydrogenation and polymerization pathways according to the density functional theory calculations. ZVMg corroded for 14 days illustrated a long-term chemical stability and excellent degradation performance, demonstrating significant application potential in remediating the TCE plumes in groundwater.

Copper loaded carbon aerogel from chitosan-precursor promotes thermal decomposition of ammonium perchlorate for solid propellants

Chitosan (CS) was used as a carrier, in which copper particles were loaded, and CS-Cu carbon aerogel was obtained by freeze-drying and high-temperature carbonization, which was characterized by scanning electron microscopy test, Fourier transform infrared spectroscopy test, X-ray diffraction test, X-ray photoelectron spectroscopy, and gas adsorption method. Results show that CS-Cu carbon aerogel is a 3D porous material, and its 3D porous structure provides more active sites for the copper nanoparticles, effectively preventing the agglomeration phenomenon caused by the large surface energy of copper nanoparticles. The CS-Cu carbon aerogel was introduced into the solid propellant system, and the catalytic performance of the CS-Cu carbon aerogel on ammonium perchlorate (AP) was investigated by differential thermal analysis. The results show that the CS-Cu carbon aerogel has good catalytic performance, the high temperature decomposition peak of AP is reduced by 92.4 K and the activation energy is reduced from 215.9 ± 1.3 kJ/mol to 173.7 ± 1.5 kJ/mol for pure AP.

Nanoparticles Surface Energy Effect on Mechanical Properties and Microscopic Deformation of 3D Heterogeneous Nanostructures

Nanoparticle-contained graphene foam material has attracted many practical applications in recent years, which require an in-depth comprehension of the basic mechanics of these heterogenous materials. In this paper, the effect of nanoparticles surface energy on the mechanical properties of nanoparticle-filled graphene foam under uniaxial tension and compression is systematically studied by the coarse-grained molecular dynamics simulation method. The mechanical strength of these nanoparticle-filled graphene foam is directly influenced by tuning the nanoparticles surface energy. The varying peeling-off behaviors of graphene sheets influenced by the surface energy of nanoparticles are observed. The stress distribution under uniaxial compression and tension at different nanoparticles surface energy is also studied. The mechanical behavior of nanoparticle-filled graphene foam is directly dependent on nanoparticles surface energy. The results should be helpful not only to understand the micro mechanism of such nanomaterials, but also to the design of advanced composites and devices based on porous materials mixed with particles.

Improvement of electrochromic performance of nickel oxide porous films by Sn doping

In order to alleviate some disadvantages such as slow switch speed, small light modulation, and poor cycle stability, which hinder the large-scale application of electrochromic (EC) materials, element doping has become one of important routes to improve their microstructure and performance. In this work, tin-doped nickel oxide (Sn-doped NiO) porous EC films were prepared, and the influence of Sn-doping amount on the microstructure and EC performance of NiO films was investigated by comparing with undoped NiO film. Based on the electrochemical tests and energy-band structure analyses, the influence mechanism of Sn doping was discussed. The results show that the Sn doping changed the surface energy of NiO nanoparticles, and then changed the microstructure, increased the diffusion rate of ions, and improved the light modulation of NiO films obviously. And the Sn doping reduced the interface barrier of FTO/NiO heterojunction, resulting into the rapid EC response. The Sn-doped NiO film with doping amount of 10.0 mol.% showed the best EC properties, including large light modulation (64.1% at 550 nm), short response time (0.4 s for bleaching time and 3.0 s for coloring time), high coloration efficiency (48.9 cm2 C−1), and long cycle life (30000 cycles), and its semiconductor type changed into n-type from the p-type of undoped NiO film.

Evolution of the surface energy of BaTiO3 nanoparticles in the course of dispersant coating: An inverse gas chromatography study

Understanding the surface energy characteristics of nanoparticles is crucial for controlling their stability, dispersion, and subsequent material properties. In this study, we employed inverse gas chromatography (IGC) to investigate the changes in surface energy and its homogeneity of BaTiO3 nanoparticles during coating with a model dispersant, stearic acid (SA), at various coverage levels. The IGC results revealed that the SA coating led to a more stable and homogeneous dispersive surface energy, enhancing the overall stability of the nanoparticles. However, it also introduced heterogeneity in the specific surface energy, with a notable shift towards higher levels. The observed evolution of surface energy characteristics was consistent with trends of the adlayer formation as determined through conventional surface characterization techniques, including thermogravimetric analysis-gas chromatography mass spectrometry and diffuse reflectance infrared Fourier transform spectroscopy. The combined approach of IGC and conventional techniques suggested that the changes in surface energy characteristics were associated with the formation of a disordered organic adlayer through SA chemisorption at various surface sites on crystalline facets with diverse coordination configurations. This highlights the potential of IGC as a powerful monitoring tool for investigating molecular coatings on ceramic nanopowders. It enables not only the quantification of average surface states but also provides insights into their distribution, which is not practically achievable through other surface characterization techniques.

Biofabrication of Poly(aryletherketone)‐Hydroxyapatite Composite Scaffolds via Low‐Temperature Printing

AbstractInorganic nanoparticles doped into polymer can improve osteogenesis through structural and biological cues. However, the composite implants may be unsatisfactory partly due to the high surface energy of nanoparticles contributing to aggregation and inhomogeneity, resulting in impaired properties. Herein, poly(aryletherketone) bearing carboxyl groups (PAEK‐COOH) is synthesized, and fabricated to composites with nanohydroxyapatite (nHA) via chemical binding. The composites can be formulated to homogeneous and stable bioinks in solution, and the bioinks are fabricated to porous scaffolds via low‐temperature printing, avoiding high‐temperature damage to chemical integrations and bioactive factors. The composite scaffolds present uniform distribution of elements on the surface and mechanical properties are well‐matched with those of trabecular bone. The in vitro experiments show that the addition of nHA is conducive to promote cellular proliferation and induce osteogenic differentiation of cells. Therefore, this work develops a method to prepare uniform composites, and the composite scaffolds have the potential to be used in orthopedic applications.

Rheological Properties and Structural Build-Up of Cement Based Materials with Addition of Nanoparticles: A Review

Nanoparticles improve the mechanical properties and durability of cement-based materials. However, owing to the high surface energy and specific surface areas of nanoparticles, the packing characteristic of cementitious particles will be affected. With the action of the electrostatic attraction and Van der Waals force, the cementitious particles are agglomerated into flocculation structures, and the free water is entrapped. Furthermore, as the water consumption of cement-based materials increases, the flowability gets worse, which is thought to be one of the reasons limiting its application in practical engineering. In addition, nanoparticles increase the viscosity and thixotropy of fresh cement-based materials and provide more nucleation sites in cement paste, accelerating the cement hydration process in early hydration. In this paper, the research progress on the rheological properties and structural build-up of cement-based materials with the addition of nanoparticles was reviewed. The applicability of rheological test methods and rheological models was summarized. The variation of rheological parameters of fresh cement-based materials affected by nanoparticles species, contents, dispersion method, superplasticizer, etc., were discussed. Based on the packing density, water film thickness, and flocculation structures, the action mechanism of nanoparticles on the rheological properties of cement-based materials was analyzed. Further research topics on the rheology and structural build-up of nano-modified cement-based materials are suggested as well.

Theoretical analysis of thermo-responsive behavior of microgels loaded with silver nanoparticles

Temperature is one of the extremely significant factors which is responsible for modifications mostly in physical but also in chemical properties of some particular matter. In present study, we carried out theoretical analysis of thermo-responsive behavior of Ag-p (N-isopropylmethacrylamide) hybrid microgels. We employed the classical Maxwellian distribution function with respect to the velocity of spherical silver nanoparticles inside the microgel’s network. The behavior of distribution function relative to the temperature represents that the distribution function still obeys the Maxwell-Boltzmann law even at low temperatures. Further, the diffusion coefficient, probability density, surface tension and surface energy of silver nano-particles are numerically evaluated and then graphically illustrated.

Generic prediction of exocytosis rate constants by size-based surface energies of nanoparticles and cells

Nanotechnology brings benefits in fields such as biomedicine but nanoparticles (NPs) may also have adverse health effects. The effects of surface-modified NPs at the cellular level have major implications for both medicine and toxicology. Semi-empirical and mechanism-based models aid to understand the cellular transport of various NPs and its implications for quantitatively biological exposure while avoiding large-scale experiments. We hypothesized relationships between NPs-cellular elimination, surface functionality and elimination pathways by cells. Surface free energy components were used to characterize the transport of NPs onto membranes and with lipid vesicles, covering both influences by size and hydrophobicity of NPs. The model was built based on properties of neutral NPs and cells, defining Van de Waals forces, electrostatic forces and Lewis acid–base (polar) interactions between NPs and vesicles as well as between vesicles and cell membranes. We yielded a generic model for estimating exocytosis rate constants of various neutral NPs by cells based on the vesicle-transported exocytosis pathways. Our results indicate that most models are well fitted (R2 ranging from 0.61 to 0.98) and may provide good predictions of exocytosis rate constants for NPs with differing surface functionalities (prediction errors are within 2 times for macrophages). Exocytosis rates differ between cancerous cells with metastatic potential and non-cancerous cells. Our model provides a reference for cellular elimination of NPs, and intends for medical applications and risk assessment.