Self-assembled Nanocomposites Research Articles

Magnetic Solid Phase Extraction Tool Based on Halloysite Modified Chitosan Self-Assembled Graphene Oxide 3d-Structured Nanocomposite

Magnetic Solid Phase Extraction Tool Based on Halloysite Modified Chitosan Self-Assembled Graphene Oxide 3d-Structured Nanocomposite

Ultrahigh In-Plane Thermoelectric Performance in Self-Assembled PbSe:Au Films With Vertically Aligned Nanopillar

Self-assembled nanocomposites with tunable physical properties have potential applications in advanced devices. In this work, self-assembled PbSe:Au films with vertically aligned nanopillars (VAN) were fabricated by pulsed laser deposition. Detailed heterostructures with atomic-resolution have been investigated by cross-sectional scanning tunnelling microscopy. The results show that self-assembled Au nanopillars in a PbSe matrix is realized. Compared with PbSe matrix, PbSe:Au vertical interface can facilitate energy filter effect and lower the in-plane thermal conductivity. The maximum ZT values for n-type self-assembled VAN film is ~2.6 at 523 K, which is ~400% higher than that of pure PbSe film (ZT=0.5). This study suggests that the vertical interface in the unique VAN provide a viable route to manipulate the thermoelectric properties for the thermoelectric materials.

Effect of a Novel Hybrid Nanocomposite of Cisplatin-Chitosan on Induced Tissue Injury as a Suggested Drug by Reducing Cisplatin Side Effects.

The self-assembly of cisplatin (Cis-Pt) and chitosan nanoparticles (Cs NPs) has been synthesized and characterized successfully by different analyses and techniques, such as scanning electron microscopy, ultraviolet-visible spectrophotometry, and Fourier transform infrared spectroscopy. The efficiency of loading Cis-Pt on Cs NPs for decreasing the side effects of Cis-Pt by loading it on Cs NP surface was revealed through histopathological and physiological measurements for the liver, testis, and kidney cells. Self-assembly hybrid nanocomposite (Cis-Pt@Cs) could improve spermatogenic cells, seminiferous tubules, and Leydig cells in the interstitial tissue. Kidney examination showed intact glomeruli with a mild increase in capsular space in addition to the intact renal tubular epithelial lining, and liver findings showed improvement in dilation and congestion of the central vein besides mild dilation of blood sinusoids in addition to a mild degree of hepatocyte vacuolation. The serum levels of hepatic, renal, and testicular marker analysis were measured, where Cis-Pt increased the serum levels of alanine aminotransferase, aspartate aminotransferase activity, urea, creatinine, and decreased testosterone levels, while synthesized self-assembly appeared normalized levels. From the results, the self-assembly hybrid nanocomposite decreases and improves the side effects of Cis-Pt.

Self-Assembled Triple (H+/O2-/e-) Conducting Nanocomposite of Ba-Co-Ce-Y-O into an Electrolyte for Semiconductor Ionic Fuel Cells.

Triple (H+/O2−/e−) conducting oxides (TCOs) have been extensively investigated as the most promising cathode materials for solid oxide fuel cells (SOFCs) because of their excellent catalytic activity for oxygen reduction reaction (ORR) and fast proton transport. However, here we report a stable twin-perovskite nanocomposite Ba-Co-Ce-Y-O (BCCY) with triple conducting properties as a conducting accelerator in semiconductor ionic fuel cells (SIFCs) electrolytes. Self-assembled BCCY nanocomposite is prepared through a complexing sol–gel process. The composite consists of a cubic perovskite (Pm-3m) phase of BaCo0.9Ce0.01Y0.09O3-δ and a rhombohedral perovskite (R-3c) phase of BaCe0.78Y0.22O3-δ. A new semiconducting–ionic conducting composite electrolyte is prepared for SIFCs by the combination of BCCY and CeO2 (BCCY-CeO2). The fuel cell with the prepared electrolyte (400 μm in thickness) can deliver a remarkable peak power density of 1140 mW·cm−2 with a high open circuit voltage (OCV) of 1.15 V at 550 °C. The interface band energy alignment is employed to explain the suppression of electronic conduction in the electrolyte. The hybrid H+/O2− ions transport along the surfaces or grain boundaries is identified as a new way of ion conduction. The comprehensive analysis of the electrochemical properties indicates that BCCY can be applied in electrolyte, and has shown tremendous potential to improve ionic conductivity and electrochemical performance.

Versatile self-assembled MXene-Au nanocomposites for SERS detection of bacteria, antibacterial and photothermal sterilization

The emergence of antibiotic-resistant bacterial strains has caused bacterial infections to become a more serious worldwide health problem. The development of multi-functional platform that can quickly and sensitively detect bacteria and effectively inhibit or kill bacterial is important and urgent. Herein, a novel versatile MXene-Au nanocomposite was successfully synthesized by self-assembly method for rapid detection of bacteria and photothermal sterilization. The typical gram-negative Escherichia coli (E. coli) and the gram-positive Bacillus subtilis (B. subtilis) were used as models to perform label-free, rapid and sensitive detection of bacteria based on SERS method. The antibacterial performance of the material was proved by the colony counting method, and the survival rates of E. coli and B. subtilis were as low as 8.05% and 0.06%, respectively. The Ti3C2Tx-Au nanoparticles (NPs) irradiated with 808 nm light showed significant antibacterial effect within only 6 min, and the germicidal rates for E. coli and B. subtilis were 99.25% and 100%, respectively. The photothermal conversion efficiency reached as high as 43.40%. Accordingly, this multi-functional nanocomposite material can not only detect bacteria sensitively, but also has antibacterial and photothermal sterilization effects, which provides a greatly promising countermeasure for clinical treatment of diseases caused by multi-drug resistant bacteria.

Tuneable interplay of plasmonic and molecular excitations in self-assembled silver - fullerene nanocomposites

Elaboration of functional hybrid nanostructures integrating noble metal nanoparticles (NPs) is an attractive topic in nanoplasmonics prompting unique technologies. Here we report on remarkable plasmonic properties of the self-assembled AgxC60 nanocomposite (NC) films, consisting of dense 3D-assembly of small Ag NPs and supporting C60 medium. Systematic study of optical absorption spectra allowed us to disclose the spectral peculiarities of plasmonic and molecular excitations in the AgxC60 NC films in the broad range of Ag concentrations, 0<x < 30. Analysis of the plasmonic modes evaluated in this study designates intriguing features of the Ag NP plasmonic coupling, which are found to be rather different in the NC films with x<10 and x>15. We found that increase of x in the range of 0<x < 10 results in strong enhancement of the electric dipole plasmon mode, whereas optical spectra of the NC films with x > 15 demonstrate pronounced efficiency of tunnelling charge transfer plasmons. Careful analysis of the detected excitations revealed evident conformity in the x-induced alterations of the plasmonic and excitonic modes as hallmarks of plasmon–exciton interactions. The detected plasmonic effects demonstrate great potential of this metal-organic system in molecular sensing, photocatalysis and optoelectronics.

Self-assembled caseinate-laponite® nanocomposites for curcumin delivery

In this study, novel self-assembled protein-clay nanocomposites were developed for curcumin delivery. Experimentally, curcumin was dissolved and deprotonated in sodium caseinate-laponite® (NaCas-LAP) dispersion at pH 12.0 for 30 min followed by neutralization to pH = 7. Due to the pH-mediated dissociation and re-association process, curcumin was successfully encapsulated into NaCas-LAP nanocomposites. The colloidal properties and encapsulation capabilities of NaCas-LAP nanocomposites were investigated, including particle size, zeta potential, encapsulation efficiency, release profile in simulated gastrointestinal tract, as well as nanoscale morphology. The results indicated that upon neutralization, NaCas-LAP nanocomposites were re-associated into smaller particles due to strong hydrophobic interactions among NaCas, LAP and curcumin. Specifically, 0.10% curcumin loaded nanocomposites prepared with 2% NaCas and 0.5% LAP showed improved encapsulation performance (73.4%) with smaller particle size (100 nm). The as-prepared protein-clay nanocomposites hold promising potential to deliver lipophilic bioactive compounds, such as curcumin.

Effectively Promoting Activity and Stability of a MnCo2O4-Based Cathode by In Situ Constructed Heterointerfaces for Solid Oxide Fuel Cells.

The development of multiphase composite electrocatalysts plays a key role in achieving the efficient and durable operation of intermediate-temperature solid oxide fuel cells (IT-SOFCs). Herein, a self-assembled nanocomposite is developed as the oxygen reduction reaction (ORR) catalyst for IT-SOFCs through a coprecipitation method. The nanocomposite is composed of a doped (Mn0.6Mg0.4)0.8Sc0.2Co2O4 (MMSCO) spinel oxide (84 wt %), an orthorhombic perovskite phase (11.3 wt %, the spontaneous combination of PrO2 additives and spinel), and a minor Sc2O3 phase (4.7 wt %). The surface of the (Mn0.6Mg0.4)0.8Sc0.2Co2O4 phase is activated by the self-assembled nanocoating with many heterogeneous interfaces. Thence, the ORR kinetics is obviously accelerated and an area-specific resistance (ASR) of ∼0.11 Ω cm2 is obtained at 750 °C. Moreover, a single cell with the cathode shows a peak power density (PPD) of 1144.1 mW cm-2 at 750 °C, much higher than that of the cell with the MnCo2O4 cathode (456.2 mW cm-2). An enhanced stability of ∼120 h (0.8 A cm-2, 750 °C) is also achieved, related to the reduced thermal expansion coefficient (13.9 × 10-6 K-1). The improvement in ORR kinetics and stability can be attributed to the refinement of grains, the formation of heterointerfaces, and the enhancement of mechanical compatibility.

Self-assembled ZnO-rGO nanocomposite, a solid-state transformation to control its crystallite size

Nano-structured ZnO and reduced graphene oxide composites (ZnO-rGO) were self-assemble obtained via hydrothermal process. The composites were synthetized under hydrothermal conditions, using different amounts of a binder agent, in order to control the anchorage between the precursors (ε-Zn(OH)2 and graphene oxide). Afterwards, a heating treatment was performed to induce the self-assembly of phases. Results indicates that a few layer graphene oxide was obtained with an average thickness of 6 sheets. X-Ray diffraction and Rietveld analysis revealed that it is possible to obtain ZnO nanoparticles with crystallite size of around 15 nm, while the thermogravimetric analysis showed ~70 wt% of ZnO. The characterization by scanning-transmission electronic microscopy evinced that the ZnO nanoparticles were well distributed and anchored between and over the rGO sheets, forming at the same time a microporous structures with surface areas up to 78 m2/g. Therefore, the control of crystallite size of ZnO particles in the composite material was successfully carried out, promoting a good interaction between the metal oxide and the rGO sheets. Finally, electrochemical impedance spectroscopy evaluation was performed, and the results confirmed the codependency between the structural and physicochemical characteristics with the electrical conductivity. Hence, the formed materials are expected to have high capacity and stability if used as electrode of lithium-ion batteries.

Inhibiting in situ phase transition in Ruddlesden-Popper perovskite via tailoring bond hybridization and its application in oxygen permeation

Inhibiting in situ phase transition in Ruddlesden-Popper perovskite via tailoring bond hybridization and its application in oxygen permeation

Antibacterial Photodynamic Gold Nanoparticles for Skin Infection.

Damage or injury to the skin creates wounds that are vulnerable to bacterial infection, which in turn retards the process of skin regeneration and wound healing. In patients with severe burns and those with chronic diseases, such as diabetes, skin infection by multidrug-resistant bacteria can be lethal. Therefore, a broad-spectrum therapy to effectively eradicate bacterial infection through a mechanism different from that of antibiotics is much sought after. We successfully synthesized antibacterial photodynamic gold nanoparticles (AP-AuNPs), which are self-assembled nanocomposites of an antibacterial photodynamic peptide and poly(ethylene glycol) (PEG)-stabilized AuNPs. The AP-AuNPs exhibited aqueous and light stability, a satisfactory generation of reactive oxygen species (ROS), and a remarkable antibacterial effect toward both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli upon light irradiation. Moreover, the synthesized nanocomposites significantly inhibited bacterial growth and biofilm formation in vitro. Photodynamic antibacterial treatment accelerated the wound-healing rate in S. aureus infections, mimicking staphylococcal skin infections. Using a combination of the bactericidal effect of a peptide, the photodynamic effect of a photosensitizer, and the multivalency clustering on AuNPs for maximal antibacterial effect under light irradiation, we synthesized AP-AuNPs as a wound-dressing nanomaterial in skin infections to promote wound healing. Our findings indicate a promising strategy in the management of bacterial infections resulting from damaged skin tissue, an aspect that has not been fully explored by our peers.

Review on soft magnetic metal and inorganic oxide nanocomposites for power applications

• Summary of the state-of-the-art soft magnetic materials and applications in power electronics. • Characteristics of oxide-based, metal-insulator, and insulator-insulator type composites. • Overview on thermodynamics and kinetics of self-assembled nanocomposites. • Microstructure engineering of soft magnetic composites based on traditional and advanced powder processing techniques. Oxide-based nanocomposites have potential to offer much higher switching frequencies compared with state-of-the-art soft magnetic materials for applications in power electronics. However, scalable techniques for synthesizing high performance bulk oxide-based nanostructured and nanocomposite systems with superior performance compared to traditional materials are limited. This review aims at identifying existing and potential opportunities for the development of high performance nanocomposite systems through microstructure engineering specific to soft magnetic property optimization by traditional processing routes. The review begins with general introduction about soft magnetic properties of different classes of materials, followed by a detailed description of crystal structures and the underlying physics responsible for their magnetic performance. These include; soft ferrites, bulk crystalline alloys, metal-amorphous nanocomposites, and metal-oxide nanocomposites of various nature such as metal-insulator and insulator-insulator type composites. An overview on powder metallurgy techniques is provided and aspects relevant to optimizing the balance between competing requirements of high effective electrical resistivity to mitigate eddy current losses and high saturation magnetization are highlighted.

Review on the growth, properties and applications of self-assembled oxide-metal vertically aligned nanocomposite thin films-current and future perspectives.

Self-assembled oxide-metal nanocomposite thin films have aroused great research interest owing to their wide range of functionalities, including metamaterials with plasmonic and hyperbolic optical properties, and ferromagnetic, ferroelectric and multiferroic behaviors. Oxide-metal nanocomposites typically self-assemble as metal particles in an oxide matrix or as a vertically aligned nanocomposite (VAN) with metal nanopillars embedded in an oxide matrix. Among them, the VAN architecture is particularly interesting due to the vertical strain control and highly anisotropic structure, enabling the epitaxial growth of materials with large lattice mismatch. In this review, the driving forces behind the formation of self-assembled oxide-metal VAN structures are discussed. Specifically, an updated in-plane strain compensation model based on the areal strain compensation concept has been proposed in this review, inspired by the prior linear strain compensation model. It provides a guideline for material selection for designing VAN systems, especially those involving complex orientation matching relationships. Based on the model, several case studies are discussed, comparing the microstructure and morphology of different oxide-metal nanocomposites by varying the oxide phase. Specific examples highlighting the coupling between the electrical, magnetic and optical properties are also discussed in the context of oxide-metal nanocomposites. Future research directions and needs are also discussed.

Tracking the emergence of epitaxial metal-oxide interfaces from precursor alloys.

Heterointerfaces with an epitaxial relationship, self-assembled nanocomposites of Pt(111)/CeO2(111) 60°, were successfully formed by simple oxidation of Pt5Ce alloy. Oxygen dissolution into the alloy causes spacial periodic compositional perturbation by atomic segregation, specifically, by local diffusion of Pt and Ce atoms. A striped pattern of Pt and CeO2 with a 4-5 nm periodicity formed through phase transformation of the Pt-rich alloy and oxidation of the Ce-rich alloy, respectively. Notably, a fully epitaxial relationship between the Pt and CeO2 phases was observed even in the initial stage. With continued annealing, the crystals rotated into an energetically favorable orientation with respect to the remaining (111)Pt//(111)CeO2. The alloy oxidation and its resulting nanoscale phase-separation behavior were verified in an ex situ annealing experiment of an alloy specimen, which had been first thinned by a focused ion beam. Changing the oxygen partial pressure to the reaction interface may alter the orientation relationship between the hexagonal close-packed Pt5Ce structure and face-centered cubic Pt/CeO2 structure, thereby altering the growth direction of the separated phases. These findings present a pathway for the self-assembly of epitaxial Pt(111)/CeO2(111) interface and are expected to assist the structural design of metal-oxide nanocomposites.

Revisiting the Old and Golden Inorganic Material, Zirconium Phosphate: Synthesis, Intercalation, Surface Functionalization, and Metal Ion Uptake

As a fascinating two-dimensional (2D) layered inorganic ion exchange material, zirconium phosphate (hereafter ZrP) has drawn interdisciplinary attention as an ion exchange material and a competent host for surface functionalization and intercalation. This is due to its captivating properties such as simple synthesis procedure, excellent ion-exchange capacity, excellent chemical, thermal, and radiolytic stability, tunable interlayer gallery, and good biocompatibility. Among all the well-known phases of ZrP, we restrict our discussion only to the alpha (α-ZrP) and gamma (γ-ZrP) phases for their efficient ion exchange performance and more tunable interlayer spacing. This review summarizes a panorama of the recent research progress on the synthesis, intercalation, and surface functionalization of ZrP with organic molecules, metal complexes, and metal ions for the design and fabrication of self-assembled monolayers, layer-by-layer assemblies, and nanocomposites. Within the confined gallery microenvironment of ZrP, usual molecules behave unusually with dramatic enhancement in the photophysical properties. The intercalation of metal complexes and their fascinating electronic properties will also be comprehensively highlighted in this review. Furthermore, for the first time, a cutting-edge advancement (2010 onward) of the versatile adsorption performance of ZrP-based materials for the uptake of toxic metal ions which include nuclear waste-related metal ions, heavy metal ions, and rare earth ions will be presented in detail. Last but not least, the review will conclude with the summary and future directions, which will provide new research opportunities for the development of ZrP based sustainable heterofunctional material.

Revealing a metastable cubic phase in CoFe2O4–SrTiO3 three-dimensional network heteroepitaxial nanostructure

CoFe2O4–SrTiO3 nanostructured thin films grown on a SrTiO3 (001) substrate are typical self-assembled vertical heteroepitaxial nanocomposites (VHNs) with CoFe2O4 nanopillars embedded into a SrTiO3 matrix. When the film thickness increased from ∼20 nm to ∼80 nm, a new three-dimensional network heteroepitaxial nanostructure in which a SrTiO3 core surrounded by a CoFe2O4 rhombus boundary was created. A new metastable CoFe1.48O3.22 cubic structure formed between the CoFe2O4 and SrTiO3 matrix/substrate as a result of the local strain field at a CoFe2O4/SrTiO3 interface forcing a part of tetrahedral Fe cations in CoFe2O4 to diffuse into the adjacent SrTiO3. Compared with the VHN structure, the new three-dimensional network heteroepitaxial nanostructure enhanced the perpendicular magnetic anisotropy mainly due to the shape anisotropy.

Facile preparation and highly efficient photodegradation performances of self-assembled Artemia eggshell-ZnO nanocomposites for wastewater treatment

Water pollution is an urgent problem in the world today. The discharge of industrial wastewater such as organic dyes will cause serious pollution to water bodies, thereby affecting people's lives. Facing the increasingly severe water pollution problem, the demand for efficient dye degradation materials is also increasing. Artemia cyst shell (ACS), as a natural biological material, has a large number of microporous structures, so it can be used as a carrier for high-efficiency nanoscale catalytic materials. In this work, ACS-ZnO nanocomposites were successfully synthesized by a combination of high-temperature calcination and hydrothermal synthesis, and their properties and photocatalytic degradation properties for dyes were studied. Artemia cyst shells are calcined at high temperature to form an organic porous skeleton after pretreated. The structure is then loaded with ZnO nanoparticles to synthesize the target product through a hydrothermal reaction. Finally, the material is used to degrade methylene blue, Rhodamine B, and neutral red respectively under light irradiation. The results show that the photodegradation effect of ACS-ZnO nanocomposites with a certain ZnO content is significantly stronger than that of pure ZnO nanoparticles. At the same time, cyclic experiments show the high stability and sustainable use of this composite material.

Preparation of self-assembled N-Zn2GeO4 nanocomposite and their photocatalytic properties

Preparation of self-assembled N-Zn2GeO4 nanocomposite and their photocatalytic properties

Micellar nanocomposites hydrogels films for pH sensitive controlled drug delivery

Hydrogels thin films with self-assembled surfactant micellar nanocomposites microstructures were prepared by a simple, green and cost effective approach. We have developed, gelatin/sodium dodecyl sulfate (SDS)/sodium alginate blend film with CaCl2 as cross linking agent. A uniform distribution of spherical micelles of the size 20 ± 2 nm, below its critical micellar concentration was clearly seen in the film matrix. The film showed improved drug loading, controlled drug delivery and biocompatibility. The film were flexible, swellable and sensitive to pH, to be used as a vaginal drug delivery system.

Self-assembly of carbon nanotube/graphitic-like flake/BiOBr nanocomposite with 1D/2D/3D heterojunctions for enhanced photocatalytic activity

A self-assembled nanocomposite of lamellar BiOBr covalently bonded with conductive network of dispersive one-dimensional carbon nanotubes (1D CNT) and two-dimensional reduced graphitic-like flakes (2D GF) had been in situ constructed using one-pot facile solvothermal technique. Through self-assembly, BiOBr/CNT/GF (BiOBr/CG) displayed three-dimensional architectures in which a strong interfacial contact interaction and covalent banding between BiOBr nanostructures and CNT/GF network appeared. Furthermore, visible-light-driven catalytic activity of BiOBr/CG for RhB dye degradation was superior to that of pure BiOBr or BiOBr/C. Interestingly, the photodegradation activity of the BiOBr/CG nanocomposite could be improved further by subsequent facile annealing treatment, in which the annealed BiOBr/CG-DS had degraded almost 97.9% of RhB dye within only 100 min of visible-light irradiation. Moreover, analysis of the photodegradation mechanism revealed that the repression of electron-hole recombination in the nanocomposites, with sufficient covalent interfacial contact with CNT/GF as effective electron collecting and transferring system, were responsible for the outstanding photocatalytic performance. This effect, in turn, led to the continuous generation of O2− and OH reactive oxygen species for the degradation of RhB dye, which was verified by active species trapping and ESR spectra.