Versatile Route Research Articles

Experimental analysis of effect of speed and time on aluminium nanoparticles fabricated by high energy ball milling

Metal Matrix Composites are technologically advance material identified in recent era as a substitute for traditional engineering materials because of their excellent properties. Out of the available material, demand for Aluminium Matrix Composites are increasing in the sector of aerospace, automobile and defense applications. The Aluminium Matrix Composites are majorly accepted because of their excellent physical and mechanical properties. There are various manufacturing techniques developed for the fabrication of AMCs. High energy ball milling is a one of the most effective and versatile routes for fabrication of nano aluminium powder. The Al powder of 99.55% purity was taken for experimentation. The 60gm of Al powder was taken in stainless steel vial with BPR as 5:1. The stainless steel balls of diameter 4mm was used as a grinding media. The ball milling was performed at different speed and time in presence of 60ml toluene as process control agent. The characterization of powder particle was done with XRD and SEM. The analysis of peak were done on origin software. The optimum speed and milling time for fabrication of Al nanoparticles of size 36 nm were found to be at 250rpm and 3 to 6 hours.

Nanocomposite Materials Based on TMDCs WS2 Modified Poly(l-Lactic Acid)/Poly(Vinylidene Fluoride) Polymer Blends.

Novel multifunctional biopolymer blend nanocomposites composed of poly(vinylidene fluoride)(PVDF) and tungsten disulfide nanotubes (INT-WS2) that are layered transition metal dichalcogenides (TMDCs) were easily prepared by applying an economical, scalable, and versatile melt processing route. Furthermore, their synergistic effect to enhance the properties of poly(L-lactic acid) (PLLA) matrix was investigated. From morphological analysis, it was shown that the incorporation of 1D (INT)-WS2 into the immiscible PLLA/PVDF mixtures (weight ratios: 80/20, 60/40, 40/60, and 20/80) led to an improvement in the dispersibility of the PVDF phase, a reduction in its average domain size, and consequently a larger interfacial area. In addition, the nanoparticles INT-WS2 can act as effective nucleating agents and reinforcing fillers in PLLA/PVDF blends, and as such, greatly improve their thermal and dynamic-mechanical properties. The improvements are more pronounced in the ternary blend nanocomposites with the lowest PVDF content, likely due to a synergistic effect of both highly crystalline PVDF and 1D-TMDCs nano-additives on the matrix performance. Considering the promising properties of the developed materials, the inexpensive synthetic process, and the extraordinary properties of environmentally friendly and biocompatibe 1D-TMDCs WS2, this work may open up opportunities to produce new PLLA/PVDF hybrid nanocomposites that show great potential for biomedical applications.

Chemically and physically crosslinked lignin hydrogels with antifouling and antimicrobial properties

As the second most abundant polymer on earth, lignin has been largely underestimated as biomaterial in the biomedical field. In this work, we proposed a strategy to transform lignin into noncytotoxic functional hydrogel with antifouling and antimicrobial properties. A spectrum of lignin hydrogels was prepared by free radical polymerization of sulfobetaine methacrylate (SBMA) and partially methacrylated lignin (lignin-MA), where lignin-MA served as hydrogel skeleton and antibacterial agent. The formation of a double network structure consisting of chemical and physical crosslinking between SBMA and lignin-MA was confirmed. Moreover, the lignin/SBMA hydrogels demonstrated high hydrophilicity due to the hydration of the zwitterionic SBMA, which can effectively reduce protein adsorption as well as prevent bacteria attachment, resulting in much better antifouling property relative to the commonly employed biomedical material poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels. Antimicrobial property of the hydrogel was significantly enhanced with the addition of lignin, showing the best reduction rate of 94.8 % against E. coli and 95.7 % against S. aureus with 40 % lignin-MA, notably higher than the respective 80.6 % and 81.5 % reduction rates for the PSBMA hydrogel without lignin. More importantly, the biocompatibility of lignin hydrogels was retained. This study presented a facile and versatile route for incorporating lignin derivative into biomaterials to achieve excellent antifouling and antimicrobial properties, which may lead to potential applications in medical devices and biological material fields.

Mechanistic Insights of Mg2+‐Electrolyte Additive for High‐Energy and Long‐Life Zinc‐Ion Hybrid Capacitors

AbstractAn electrolyte cation additive strategy provides a versatile route for developing high‐energy and long‐life aqueous zinc‐ion hybrid capacitors. However, the mechanisms of energy storage and Zn anode protection are still unclear in Zn‐based systems with dual‐ion electrolytes. Here, a dual charge storage mechanism for zinc‐ion hybrid capacitors with both cations and anions adsorption/desorption and the reversible formation of Zn4SO4(OH)6·xH2O enabled by the Mg2+ additive in the common aqueous ZnSO4 electrolyte are proposed. Theoretical calculations verify that the self‐healing electrostatic shield effect and the solvation‐sheath structure regulation rendered by the Mg2+ additive account for the observed uniform Zn deposition and dendrite suppression. As a result, an additional energy storage capacity of ≈50% compared to that in a pure 2 m ZnSO4 electrolyte and an extended cycle life with capacity retention of 98.7% after 10 000 cycles are achieved. This work highlights the effectiveness of electrolyte design for dual‐ion carrier storage mechanism in aqueous devices toward high energy density and long cycle life.

Bottom‐up Fabrication and Atomic‐Scale Characterization of Triply Linked, Laterally π‐Extended Porphyrin Nanotapes**

AbstractPorphyrin nanotapes (Por NTs) are promising structures for their use as molecular wires thanks to a high degree of π‐conjugation, low HOMO—LUMO gaps, and exceptional conductance. Such structures have been prepared in solution, but their on‐surface synthesis remains unreported. Here, meso–meso triply fused Por NTs have been prepared through a two‐step synthesis on Au(111). The diradical character of the on‐surface formed building block PorA2, a phenalenyl π‐extended ZnIIPor, facilitates intermolecular homocoupling and allows for the formation of laterally π‐extended tapes. The structural and electronic properties of individual Por NTs are addressed, both on Au(111) and on a thin insulating NaCl layer, by high‐resolution scanning probe microscopy/spectroscopy complemented by DFT calculations. These Por NTs carry one unpaired electron at each end, which leads to magnetic end states. Our study provides a versatile route towards Por NTs and the atomic‐scale characterization of such tapes.

A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition.

Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

Semisolid heat treatment processing window of Pb-40% Sn alloy for feedstock in the 3D printing thixo-forming process

The 3D printing thixo-forming process is a method that utilizes semisolid thixotropic feedstock for layer extrusion by controlling feedstock viscosity below the complete melting temperature of metallic alloys to form a 3D structure. The process of producing metallic feedstock has a significant impact on alloy microstructure, which is critical for the material’s printability. This study aims to propose a semisolid heat treatment processing window of Pb-40% Sn alloy for use as feedstock billets for a variety of extruder nozzles (sizes 1–3 mm) during the 3D printing thixo-forming process. Firstly, Pb-40% Sn alloys were cold deformed to reduce the specimens’ diameters. Semisolid treatments for deformed specimens were performed at a variety of semisolid heating temperatures and three separate holding times (2, 5, and 10 min). The microstructure of semisolid feedstock specimens was then investigated. The temperature and time of the semisolid heating processing window of Pb- 40% Sn alloy were optimized to feedstock specimens and thixo-extruding processes with different printed output sizes. Therefore, the proposed semisolid heat treatment processing window was a promising approach to pave the way for the low-cost manufacturing of AM, which yields higher printing rates and improved scalability of printed lines. Additionally, this approach allows for a versatile manufacturing route for producing 3D metal parts with maximum density and intricate geometries as a result of the ability to tailor the microstructure.

One-Step Template/Solvent-Free Pyrolysis for In Situ Immobilization of CoP Nanoparticles onto N and P Co-Doped Carbon Porous Nanosheets towards High-efficiency Electrocatalytic Hydrogen Evolution.

The search for economical, active and stable electrocatalysts towards the hydrogen evolution reaction (HER) is highly imperative for the progression of water electrolysis technology and related sustainable energy conversion technologies. The delicate optimization of chemical composition and architectural configuration is paramount to design high-efficiency non-precious metal HER electrocatalysts. Herein, we report a one-step scalable template/solvent-free pyrolysis approach for in situ immobilizing uniform CoP nanoparticles onto N and P co-doped carbon porous nanosheets (denoted as CoP@N,P-CNSs hereafter). The simultaneous consideration of architectural design and nanocarbon hybridization renders the formed CoP@N,P-CNSs with plentiful well-dispersed anchored active sites, shortened pathway for mass diffusion, enhanced electric conductivity, and reinforced mechanical stability. As a consequence, the optimized CoP@N,P-CNSs exhibit an overpotential of 115 mV to afford a current density of 10 mA cm-2 , small Tafel slope of 74.2 mV dec-1 , high Faradaic efficiency of nearly 100 %, and superb long-term durability in an alkaline medium. Given the fabrication feasibility, mass production potential and outstanding HER performance, the CoP@N,P-CNSs may hold great promise for large-scale electrochemical water splitting. More importantly, the explored one-step template/solvent-free pyrolysis methodology offers a feasible and versatile route to fabricate carbon nanosheet-based nanocomposites for diverse energy conversation-related applications.

Bidirectional propagation of low frequency oscillations over the human hippocampal surface

The hippocampus is diversely interconnected with other brain systems along its axis. Cycles of theta-frequency activity are believed to propagate from the septal to temporal pole, yet it is unclear how this one-way route supports the flexible cognitive capacities of this structure. We leveraged novel thin-film microgrid arrays conformed to the human hippocampal surface to track neural activity two-dimensionally in vivo. All oscillation frequencies identified between 1–15 Hz propagated across the tissue. Moreover, they dynamically shifted between two roughly opposite directions oblique to the long axis. This predominant propagation axis was mirrored across participants, hemispheres, and consciousness states. Directionality was modulated in a participant who performed a behavioral task, and it could be predicted by wave amplitude topography over the hippocampal surface. Our results show that propagation directions may thus represent distinct meso-scale network computations, operating along versatile spatiotemporal processing routes across the hippocampal body.

Direct Organometallic Synthesis of Carboxylate Intercalated Layered Zinc Hydroxides for Fully Exfoliated Functional Nanosheets

AbstractIntercalation of organic anions into 2D materials can enable exfoliation, improve dispersion stability, increase surface area, and provide useful functional groups. In layered metal hydroxides, intercalation of bulk structures is commonly achieved by cumbersome and typically incomplete anion exchange reactions. In contrast, here, a series of carboxylate‐intercalated layered zinc hydroxides (LZH‐R) are synthesized directly, at room temperature, by reacting an organozinc reagent with a precise sub‐stoichiometric quantity of the desired carboxylic acid and water. A range of carboxylic acids are used to make new LZH‐R materials which are crystalline, soluble, and functionalized, as established by X‐ray diffraction, spectroscopic, and microscopy techniques. When R is an alkyl ether carboxylate, this direct synthesis method results in the spontaneous exfoliation of the LZH‐R into monolayer nanosheets with high yields (70–80%) and high solubilities in alcohols and water of up to 180 mg mL−1. By altering the carboxylate ligand, functional groups suitable for post‐synthetic modification or for detection by fluorescence are also introduced. These examples demonstrate a versatile synthetic route for functional exfoliated nanosheets.

Swelling‐Induced Symmetry Breaking: A Versatile Approach to the Scalable Production of Colloidal Particles with a Janus Structure

AbstractJanus particles are widely sought for applications related to colloidal assembly, stabilization of emulsions, and development of active colloids, among others. Here we report a versatile route to the fabrication of well‐controlled Janus particles by simply breaking the symmetry of spherical particles with swelling. When a polystyrene (PS) sphere covered by a rigid shell made of silica or polydopamine is exposed to a good solvent for PS, a gradually increased pressure will be created inside the shell. If the pressure becomes high enough to poke a hole in the shell, the spherical symmetry will break while pushing out the swollen PS through the opening to generate a Janus particle comprised of two distinct components. One of the components is made of PS and its size is controlled by the extent of swelling. The other component is comprised of the rigid shell and remaining PS, with its overall diameter determined by the original PS sphere and the rigid shell. This solution‐based route holds promises for the scalable production of complex Janus particles with a variety of compositions and in large quantities.

Low temperature Topographically Selective Deposition by Plasma Enhanced Atomic Layer Deposition with ion bombardment assistance

Area selective deposition via atomic layer deposition (ALD) has proven its utility in elementary nanopatterning processes. In the case of complex 3D patterned substrates, selective deposition processes lead to vertical sidewall coverage only, or top and bottom horizontal surface coverage only, to enable advanced nanopatterning and further miniaturization of microelectronic devices. While many fabrication strategies for vertical only Topographically Selective Deposition (TSD) have already been developed, the horizontal TSD case needs further attention. In this work, we propose a versatile route for the TSD on 3D top and bottom horizontal surfaces along with a proof-of-concept for such selective Ta2O5 thin film deposition. The strategy at stake relies on a plasma enhanced atomic layer deposition process assisted by energetic ion bombardment during the plasma step and followed by a postgrowth wet etching step. The effectiveness of this strategy is based on a careful adjustment of processing temperatures purposely set at low temperature, most probably below the ALD temperature window. Anisotropic ion bombardment via substrate biasing during the plasma step provides an extra amount of thermal energy only to exposed horizontal surfaces, which in turn enables a selective densification of the thin film under growth. The difference in thin film density on horizontal and vertical surfaces enables the property-selective etching of vertical surfaces, generating horizontal TSD. A proof-of-concept for such low temperature TSD is shown in the case of 3D trenched substrates with an aspect ratio of 14.

Designing self-crosslinkable ternary blends using epoxidized natural rubber (ENR)/poly(ethylene-co-acrylic acid)(EAA)/poly(ε-caprolactone) (PCL) demonstrating triple-shape memory behavior

The aim of this work is developing a facile and versatile route for preparing chemically crosslinked triple-shape memory polymers (SMPs). Hence, epoxidized natural rubber(ENR)/poly(ethylene-co-acrylic acid)(EAA)/poly(ε-caprolactone) (PCL) ternary blends were fabricated using the facile melt-mixing method. Interestingly, it was observed that the resultant ternary blends could self-crosslink during molding at high temperature without need for any crosslinking agents. Differential scanning calorimeter (DSC) and dynamic mechanical analyzer (DMA) analyses revealed that all of the ternary blends have two well-separated thermal transitions (Tm, PCL and Tm, EAA) and, as a result, they exhibited triple-SM behavior. Moreover, the mechanical properties as well as shape memory effect of ternary blends were improved with carboxylation of PCL. The developed ternary blends can be considered as a promising SM material in many in-vivo and aerospace applications.

Development of Covalent Chitosan-Polyethylenimine Derivatives as Gene Delivery Vehicle: Synthesis, Characterization, and Evaluation.

There is an increasing interest in cationic polymers as important constituents of non-viral gene delivery vectors. In the present study, we developed a versatile synthetic route for the production of covalent polymeric conjugates consisting of water-soluble depolymerized chitosan (dCS; MW 6–9 kDa) and low molecular weight polyethylenimine (PEI; 2.5 kDa linear, 1.8 kDa branched). dCS-PEI derivatives were evaluated based on their physicochemical properties, including purity, covalent bonding, solubility in aqueous media, ability for DNA condensation, and colloidal stability of the resulting polyplexes. They were complexed with non-integrating DNA vectors coding for reporter genes by simple admixing and assessed in vitro using liver-derived HuH-7 cells for their transfection efficiency and cytotoxicity. Using a rational screening cascade, a lead compound was selected (dCS-Suc-LPEI-14) displaying the best balance of biocompatibility, cytotoxicity, and transfection efficiency. Scale-up and in vivo evaluation in wild-type mice allowed for a direct comparison with a commercially available non-viral delivery vector (in vivo-jetPEI). Hepatic expression of the reporter gene luciferase resulted in liver-specific bioluminescence, upon intrabiliary infusion of the chitosan-based polyplexes, which exceeded the signal of the in vivo jetPEI reference formulation by a factor of 10. We conclude that the novel chitosan-derivative dCS-Suc-LPEI-14 shows promise and potential as an efficient polymeric conjugate for non-viral in vivo gene therapy.

Enhanced Eradication of Bacterial/Fungi Biofilms by Glucose Oxidase-Modified Magnetic Nanoparticles as a Potential Treatment for Persistent Endodontic Infections.

Bacterial/fungal biofilm-mediated persistent endodontic infections (PEIs) are one of the most frequent clinical lesions in the oral cavity, resulting in apical periodontitis and tooth damage caused by loss of minerals. The conventional root canal disinfectants are poorly bio-safe and harmful to teeth and tissues, making them ineffective in treating PEIs. The development of nanomaterials is emerging as a promising strategy to eradicate disease-related bacteria/fungi. Herein, glucose oxidase (GOx)-modified magnetic nanoparticles (MNPs) were synthesized via a facile and versatile route for investigating their effects on removing PEI-related bacterial/fungal biofilms. It is found that GOx was successfully immobilized on the MNPs by detecting the changes in the diameter, chemical functional group, charge, and magnetic response. Further, we demonstrate that GOx-modified MNPs (GMNPs) exhibit highly effective antibacterial activity against Enterococcus faecalis and Candida albicans. Moreover, the antibacterial/fungal activity of GMNPs is greatly dependent on their concentrations. Importantly, when placed in contact with bacterial/fungal biofilms, the dense biofilm matrix is destructed due to the movement of GMNPs induced by the magnetic field, the formation of reactive oxygen species, and nutrient starvation induced by GOx. Also, the in vitro experiment shows that the as-prepared GMNPs have excellent cytocompatibility and blood compatibility. Thus, GMNPs offer a novel strategy to treat bacteria/fungi-associated PEIs for potential clinical applications.

Photopolymerized Porous Hydrogels.

Hydrogels are polymeric networks highly swollen with water. Because of their versatility and properties mimicking biological tissues, they are very interesting for biomedical applications. In this aim, the control of porosity is of crucial importance since it governs the transport properties and influences the fate of cells cultured onto or into the hydrogels. Among the techniques allowing for the elaboration of hydrogels, photopolymerization or photo-cross-linking are probably the most powerful and versatile synthetic routes. This Review aims at giving an overview of the literature dealing with photopolymerized hydrogels for which the generation or characterization of porosity is studied. First, the materials (polymers and photoinitiating systems) used for synthesizing hydrogels are presented. The different ways for generating porosity in the photopolymerized hydrogels are explained, and the characterization techniques allowing adequate study of the porosity are presented. Finally, some applications in the field of controlled release and tissue engineering are reviewed.

Multimodal treatment combining cold atmospheric plasma and acidic fibroblast growth factor for multi‐tissue regeneration

Cold atmospheric plasma (CAP) is an emerging technology for biomedical applications, exemplified by its antimicrobial and antineoplastic potentials. On the contrary, acidic fibroblast growth factor (aFGF) has been a long-standing potent mitogen for cells from various origins. In this study, we are the first to develop a multimodal treatment combining the aforementioned physicochemical and pharmacological treatments and investigated their individual and combined effects on wound healing, angiogenesis, neurogenesis, and osteogenesis. This work was performed at the tissue, cellular, protein, and gene levels, using histochemical staining, flow cytometry, ELISA, and PCR, respectively. Depending on the type of target tissue, various combinations of aforementioned methods were used. The results showed that the enhancement on would healing and angiogenesis by CAP and aFGF were synergistic. The former was manifested by increased murine fibroblast proliferation and reduced cutaneous tissue inflammation, whereas the latter by upregulated proangiogenic markers in vivo, for example, CD31, VEGF, and TGF-β, and downregulated antiangiogenic proteins in vitro, for example, angiostatin and angiopoietin-2, respectively. In addition, aFGF outperformed CAP during neurogenesis, which was evidenced by superior neurite outgrowth, while CAP exceeded aFGF in osteogenesis which was demonstrated by more substantial bone nodule formation. These novel findings not only support the fact that CAP and aFGF are both multipotent agents during tissue regeneration, but also highlight the potential of our multimodal treatment combining the individual advantages of CAP and aFGF. The versatile administration route, that is, topical and/or systemic, might further broaden its applications.

Wavelength-Gated Photochemical Synthesis of Phenalene Diimides.

Herein, we pioneer a wavelength‐gated synthesis route to phenalene diimides. Consecutive Diels–Alder reactions of methylisophthalaldehydes and maleimides afford hexahydro‐phenalene‐1,6‐diol diimides via 5‐formyl‐hexahydro‐benzo[f]isoindoles as the intermediate. Both photoreactions are efficient (82–99 % yield) and exhibit excellent diastereoselectivity (62–98 % d.r.). The wavelength‐gated nature of the stepwise reaction enables the modular construction of phenalene diimide scaffolds by choice of substrate and wavelength. Importantly, this synthetic methodology opens a facile avenue to a new class of persistent phenalenyl diimide neutral radicals, constituting a versatile route to spin‐active molecules.

Material Properties Modulation in Inorganic Perovskite Films via Solution-Free Solid-State Reactions

A simple solvent-free, versatile, and flexible route for material properties modulation in halide perovskite thin films has been developed using CsPbBr3 thin films. The method further enables compo...

Structure, composition and photoconductivity analysis of zinc tin phosphide ternary compound nanoparticles synthesized by chemical method

Zinc tin phosphide (ZTP) has attracted recent research interest as a low-cost light sensing material, alternative to III–V and II–III-based compounds, for photo-detector and solar cell applications. In this study, a versatile chemical route for the synthesis of ZTP nanoparticles starting from commercially available alkyl-zinc and tin, alkyl-phosphoramides and trioctylphosphine at a relatively low temperature of 160 °C is reported, which can straightforwardly be extended to other analogous II–IV-P2 group ternary compounds. The particles displayed high stability and can be deposited as layers with few monolayers of thickness. The structural and chemical analysis revealed that the particles are of sub-10 nm size with chalcopyrite structure and ZnSn-phosphide composition. The particles exhibited optical band-gap in the range of 1.65–1.75 eV and a broadband photo-response in the visible wavelengths (400–700 nm) with excellent response to red light.