Octadecylamine Research Articles

Effects of Flotation Reagents on the Morphology of Magnesium Hydroxide: Experimental and Simulation Study

The flotation process to extract potassium salt from carnallite ores could produce the MgCl2 mother liquor with flotation reagents─octadecyl amine hydrochloride (ODA) and dodecyl morpholine (DMP). The organic impurities would further affect MgCl2 resource-integrated utilization for preparing magnesium hydroxide (MH). In this study, the effects of flotation reagents with different concentrations on the morphology of MH were investigated at a hydrothermal temperature of 200 °C for 6 h with the hydrothermal medium of a 4 mol/L NaOH solution. It was observed that the average thickness of MH crystal plates increased and the morphology of crystals changed from regular hexagonal plates to irregular polygonal plates with the increase of ODA and DMP concentrations. Molecular dynamics (MD) simulation was applied to further explain the effect mechanism. The results indicated that ODA and DMP molecules were more likely to be adsorbed on the (1 1 0) plane in contrast to the (0 0 1) plane due to the larger absolute values of adsorption energy on the (1 1 0) plane. The long carbon chains far away from the (1 1 0) plane would form steric hindrance to affect the growth rate of MH crystals in the [1 1 0] direction.

A simple surface modification method to prepare versatile PVDF electrospun nanofibrous felts for separation, sterilization and degradation

The discharge of oily effluents from industrial production and crude oil spills at sea result in significant water pollution, posing a major danger to the environment and human health. Due to the tiny droplet size, emulsion separation is a difficult task in the separation and purification of oily wastewater. Polydopamine (PDA) and TiO2 nanoparticles were coated on the surface of polyvinylidene fluoride (PVDF) electrospun nanofibrous to increase surface roughness, and then the low surface energy substance octadecylamine (ODA) was grafted. As a result, a superhydrophobic PVDF@PDA/TiO2@ODA nanofibrous felts with a water contact angle of 168.1° has been developed. Because of their three-dimensional porous structure, the nanofibrous felts have a porosity of up to 72.9 %. The tensile strength of a series of reinforced PVDF@PDA/TiO2@ODA nanofibrous felts reaches 30.06 MPa, which is useful for maintaining the stability of the nanofibrous felts during the pressure separation. The oil and water in the emulsion are entirely separated due to the selective permeability induced by the strong superhydrophobic and superlipophilic properties. The separation efficiency of over 99 % and flow flux of above 1100 L·m−2·h−1 are achieved. The performance of the nanofibrous felts in inhibiting bacterial growth was then investigated, and it is found that a significant inhibition circle appeared in the flat dish diffusion method, with a bacteriostasis rate exceeding 99 %. This result demonstrates that PVDF@PDA/TiO2@ODA nanofibrous felts have excellent antimicrobial properties. Finally, UV–vis absorption spectroscopy was employed to demonstrate the good catalytic degradation of organic dyes by PVDF@PDA/TiO2@ODA nanofibrous felts. PVDF@PDA/TiO2@ODA nanofibrous felts have a variety of applications in the deep separation and purification of oily wastewater due to these characteristics.

Facile fabrication of superhydrophobic magnetic bio-waste for oil spill cleanup

In this study, we have demonstrated a facile method to convert corncob, an abundant and low-cost bio-waste, into a superhydrophobic magnetic bio-sorbent with potential application in oil spill remediation. We immobilized CoFe2O4 nanoparticles on the surface of corncob using the co-precipitation method to magnetize the surface of the bio-waste. Additionally, we applied silica and octadecylamine (ODA) coatings to create a rough and low surface energy sorbent material, respectively, which significantly improved its oil sorption capacity. The fabricated magnetic composite exhibited excellent magnetic responsivity (saturation magnetization: 32 emu/g), superhydrophobicity (water contact angle: 165˚), and superoleophilicity (oil contact angle: 0˚). The modified corncob (MCC) powder was easily separated using a magnetic field and showed oil sorption capacity 22.13, 13.33, 57.65, and 44.17 times its original weight for crude oils with API 23.5° and 29.7°, fresh and used motor oil, respectively. The fabricated bio-sorbent could be recovered and reused in oil-water separation at least 10 times, with a water contact angle and sorption capacity of 158.5˚ and 42 g/g, respectively, after 10 cycles. Furthermore, it displayed remarkable durability in corrosive media. We compared the performance of MCC powder with three different bio-wastes, including coconut husk, acorn, and rice husk, and found that MCC powder and coconut husk showed preferable performance over the others. Overall, our study provides a facile and efficient method for converting corncob and other bio-wastes into a superhydrophobic magnetic bio-sorbent for oil spill cleanup.

Development of bio degradable nanocomposites based on PLA and functionalized graphene oxide

The use of biodegradable polymers to mitigate the environmental pollution is one of the hot topics of research in the recent years. The current work presents the graphene oxide (GO) nanoparticles functionalized with two types of alkylamines (decylamine (DA) and octadecylamine (ODA)) synthesized at two different temperatures; 25 °C (GODA1 and GOODA1) and 80 °C (GODA2 and GOODA2), which were used as fillers to prepare PLA nanocomposites and their barrier, mechanical, and thermal properties were studied. The elemental analysis showed 2 wt% to 4 wt% of nitrogen content for functionalized GO, confirming the presence of alkyl chains in its structure. The reactions carried out at 80 °C (GODA2 and GOODA2) are the ones that showed the highest mass yields, registering a 7% and 50% increase in the total mass, respectively. These results were supported by X-ray diffraction (XRD), FT-IR spectroscopy and thermogravimetric Analysis (TGA) analyses. The optical microscopy images of the nanocomposites showed that the modified GO has a higher affinity than the GO with the PLA matrix, observing good dispersion at low loads of modified GO (0.2 wt%), with an increasing tendency to form agglomerates for higher loads. Furthermore, the elastic modulus of all nanocomposites showed a decreasing trend, mainly attributed to the formation of agglomerates and the decrease in the crystallinity of the composites. The oxygen permeability progressively decreases with increasing nanoparticle load, the nanocomposites prepared with GODA2 and GOODA2 presented the best results, registering decreases of 28.6% and 30.4% for 2 wt% loads, respectively. On the other hand, the permeability to water vapor decreased by 36.0% and 50.2%, for loads of 0.2 wt% of GODA2 and GOODA2, respectively. However, for higher amount of filler no significant improvements was detected. The results shows that the addition of modified GO to PLA improves its barrier properties, and that its composites could be used in food packaging.

The Mechanism of Phase Transfer Synthesis of Silver Nanoparticles Using a Fatty Amine as Extractant/Phase Transfer Agent

The paper presents the research results on synthesizing silver nanoparticles in aqueous solutions and their extraction into the organic phase. Studies have shown that it is best to perform the extraction process using n-hexane > cyclohexane > toluene > chloroform > ethyl acetate. The results show a correlation between the dielectric constant of the organic phase and its ability to extract nanoparticles. The lower the dielectric constant is, the higher the extractability. The hydrodynamic radius of the silver nanoparticles changes after transfer to the organic phase, depending greatly on the organic phase used. The extraction mechanism is complex and multi-step. As the first step, the Ag nanoparticles are transferred to the phase boundary. As the second step, the octadecylamine (ODA) molecules adsorb on the silver nanoparticles (AgNPs) surface. The change in particle shape was also noted. This suggests that the interfacial processes are more complex than previously reported. Below the initial concentration of ODA 2 × 10−4 M, the formation of a third phase has been observed. In a one-stage experiment, the concentration of silver nanoparticles after transferring to the organic phase was increased 500 times in about 10 s. The role of the concentration of ODA, therefore, is not only a measure of the extraction efficiency and productivity but functions as an enabler to maintain favorable biphasic processing, which underlines the role of the solvent again.

Effective Removal of Methyl Orange Dyes Using an Adsorbent Prepared from Porous Starch Aerogel and Organoclay

Intending to provide efficient and compact wastewater remediation, the present work is exploiting and introducing a novel composite prepared from porous starch aerogel (PSA) and organically modified Ca-montmorillonite (OMMT) for the removal of dyes from aqueous samples. First, potato starch components were used as a hydrolysis precursor to obtain PSA. The organoclay samples were prepared by co-intercalation of octadecylamine (ODA) into Ca-MMT using a low-temperature melting procedure. Composites with different starch-to-organoclay ratios of 10:1, 1:1, and 1:10 were then prepared by a blending process in distilled water and used for methyl orange (MO) uptake. The removal of methyl orange dyes increased with the amount of organoclay in the PSA matrix. Characterization revealed that organoclay synergy improved the PSA surface chemistry, while an important improvement in textural properties and thermal stability was also observed. The composite’s efficiency was demonstrated by high removal capabilities towards MO in most experimental runs, with a maximum adsorption capacity beyond 344.7 mg/g. The fitting result showed that MO adsorption follows a monolayer adsorption model, and chemisorption was the rate-controlling step. Nonetheless, this study proved the great potential of PSA/OMMT in dyeing wastewater treatment. Furthermore, starch modification is proven as an effective approach to enhancing the performance of starch-derived adsorbents.

Construction of superhydrophobic ZIF-90/Melamine sponge with highly stable puncture structure for sustainable oil spill removal from seawater

Sustainable, environmentally friendly and economically viable treatment of marine oil spills attracts a great attention. For the first time, composites with highly durable structure were prepared for continuous oil/water separation by in situ growth of zeolitic imidazole framework ZIF-90 on a porous melamine sponge (MS). First, a thin layer of metal hydroxide (Zn-LDH) was introduced on the inner wall of MS and ZIF-90 particles were loaded onto the sponge fibers by homologous induction to obtain the ZIF-90/MS composite. The thin Zn-LDH layer greatly enhanced the anchoring force of ZIF-90 on the MS skeleton to effectively avoid the crystals from piling up together. The resulting ZIF-90/MS was modified in situ with octadecylamine (ODA) to give a superhydrophobic ODA-ZIF-90/MS composite with a water contact angle (WCA) of 154o, which demonstrated great oil adsorption capacity (24–63 g/g) and excellent recoverability (98.7% absorption retention after 50 cycles). With the assistance of a pump drive, continuous separation of oil spill contaminants from actual seawater can be achieved with fluxes of 13839 g. h−1. g−1 and 13513 g. h−1. g−1 for hexane and gasoline, respectively, without any water adsorption. The highly durable ODA-ZIF-90/MS composite with puncture structure showed excellent cycling performance in oil/water separation with less than 1% ODA-ZIF-90 spillage after 50 squeeze desorption cycles. This novel integrated ODA-ZIF-90/MS composite demonstrates a promising strategy for large-scale of oil spill cleanup.

Eco‐friendly and facile modified superhydrophobic melamine sponge by molybdenum sulfide for oil/water separation

AbstractOily wastewater has caused serious damage to the human health and ecological environment. It is urgent to develop novel materials for high performance oil/water separation. Porous melamine sponges (MS) are considered as an ideal matrix material for oil/water separation. Herein, molybdenum sulfide (MoS2) modified with tannic acid (TA) and octadecylamine (ODA) was attached to MS framework via a facile dip‐coating method. This novel and eco‐friendly MS@(MoS2@ODA) sponge displays superior superhydrophobicity (WCA = 156.2°) and oil/water separation ability (absorption capacity = 113–145 g g−1). MoS2@ODA not only enhances surface roughness of MS framework, but also raises its specific surface area, causing an increase in the oil adsorption capacity of MS. Moreover, the composite sponge exhibited excellent chemical and mechanical stability. It is envisioned that this work can demonstrate a facile synthesis strategy for producing environmental friendliness MS with stable superhydrophobicity for high‐efficient oil/water separation.

Ordered Assembly of DNA on Topological Insulator Bi2Se3 and Octadecylamine for a Sensitive Biosensor.

Controlling the assembly of DNA in order on a suitable electrode surface is of great significance for biosensors and disease diagnosis, but it is full of challenges. In this work, we creatively assembled DNA on the surface of octadecylamine (ODA)-modified topological insulator (Tls) Bi2Se3 and developed an electrochemical biosensor to detect biomarker DNA of coronavirus disease 2019 (COVID-19). A high-quality Bi2Se3 sheet was obtained from a single crystal synthesized in our lab. A uniform ODA layer was coated in argon by chemical vapor deposition (CVD). We observed and analyzed the assembly and mechanism of single-strand DNA (ssDNA) and double-strand DNA (dsDNA) on the Bi2Se3 surface through atomic force microscopy (AFM) and molecular dynamics (MD) simulations. The electrochemical signal revealed that the biosensor based on the DNA/ODA/Bi2Se3 electrode has a wide linear detection range from 1.0 × 10-12 to 1.0 × 10-8 M, with the limit of detection as low as 5 × 10-13 M. Bi2Se3 has robust surface states and improves the electrochemical signal-to-noise ratio, while the uniform ODA layer guides high-density ordered DNA, enhancing the sensitivity of the biosensor. Our work demonstrates that the ordered DNA/ODA/Bi2Se3 electrode surface has great application potential in the field of biosensing and disease diagnosis.

Functionalized Magnetite Nanoparticles Using Two New Ionic Liquids for Efficient Oil Spill Cleanup

Recently, magnetite nanoparticles (MNPs) have gained great attention for oil spill cleanup due to their unique properties, e.g., high oil removal efficiency, high surface area, and response to an external magnetic field. The efficiency of MNPs for oil spill uptake can be enhanced by functionalizing their surface using different materials. Furthermore, the functionalization of MNP surface using these materials promotes their chemical stability. This study aims to functionalize the surface of magnetite nanoparticles (MNPs) using two newly synthesized hydrophobic ionic liquids (ILs) and apply them for oil spill cleanup. ILs were synthesized by the reaction of glycidyl-4-nonyl ether (GE) with fatty amines, either octadecylamine (OA) or dodecylamine (DA), to yield the corresponding amines, GEOA and GEDA, respectively. GEOA and GEDA were quaternized with acetic acid (AA) to produce the corresponding ILs, GEOA-IL and GEDA-IL. The produced ILs, GEOA-IL and GEDA-IL, were applied for the surface modification of magnetite nanoparticles (MNPs), producing surface-modified MNPs, GO-MNPs and GD-MNPs, respectively. GO-MNPs and GD-MNPs were characterized using Fourier transform infrared, X-ray diffraction, transmission electron microscopy, dynamic light scattering, contact angle, and vibrating sample magnetometer. Their oil removal efficiency (ORE) was investigated at different MNP : crude oil ratios ranging from 1 : 1–1 : 50. GO-MNPs and GD-MNPs showed high ORE even at low MNP ratios. Furthermore, GO-MNPs showed higher oil removal efficiency than GD-MNPs, which may be explained using GEOA-IL containing a longer alkyl chain for MNP surface modification in comparison to GEDA-IL. Furthermore, GO-MNPs and GD-MNPs displayed excellent reusability in five cycles, with a slight decrease in ORE with increasing cycles.

A modified QuEChERS method development to analyze tylosin and metronidazole antibiotics residue in shrimp (Penaeus monodon) using LC-ESI MS/MS

A modified QuEChERS method was developed for the simultaneous analysis of tylosin (Tyl) and metronidazole (MNZ) residues in shrimp samples using LC-ESI-MS/MS. The sample extraction procedure was based on modified QuEChERS, and the cleanup method was dispersive solid-phase extraction (dSPE). Octadecyl (C18) and primary secondary amine (PSA) sorbents were used in the dSPE cleanup. Analyte chromatographic separations were carried out using a ZORBAX RRHD Eclipse Plus C18 (100 × 2.1 mm, particle size 1.8 μm) column. The mobile phase consisted of dilluting 0.1% of formic acid with water and acetonitrile. The analyte was identified with multiple reaction monitoring and positive electrospray ionization. The analyte showed good linearity in the range of 0.5–50 μg/L for both analytes, and correlation coefficients (R2) were 0.9997 and 0.9998 for Tyl and MNZ, respectively. For the recovery study, three different concentration levels were spiked in triplicate. The recovery obtained a good result in the range of 81–85 % for Tyl with relative standard deviation (RSD) ≤ ± 4.9% and in the range of 85–88% for MNZ with RSD ≤ ± 4.07 %. The limit of detection (LOD) was estimated at 0.4 μg/kg for Tyl and 0.3 μg/kg for MNZ, and the limit of quantification (LOQ) was estimated at 1 μg/kg for Tyl and 0.9 μg/kg for MNZ. The linearity and recovery study showed that the method is validated and can be used to determine the Tyl and MNZ residues in shrimp. Finally, the method was applied to 25 real samples, which were collected from local markets and super shops in Dhaka and Khulna districts of Bangladesh, and only traces of Tyl were detected in one sample. This method is suitable for the regular analysis of Tyl and MNZ antibiotic residues in shrimp samples and can be used to ensure food safety in Bangladesh.

Probing the Mechanism of Targeted Delivery of Molecular Surfactants Loaded into Nanoparticles after Their Assembly at Oil–Water Interfaces

A targeted and controlled delivery of molecular surfactants at oil-water interfaces using the directed assembly of nanoparticles, NPs, is reported. The mechanism of NP assembly at the interface and the release of molecular surfactants is followed by laser scanning confocal microscopy and surface force spectroscopy. The assembly of positively charged polystyrene NPs at the oil-water interface was facilitated by the introduction of carboxylic acid groups in the oil phase (e.g., by adding 1 wt % stearic acid to hexadecane to produce a model oil). The presence of positively charged NPs consistently lowers the stiffness of the water-oil interface. The effect is lessened, when the NPs are present in a solution of NaCl or deionized water at pH 2, consistent with a less dense monolayer of NPs at the interface in the last two systems. In addition, the NPs reduce the interfacial adhesion (i.e., the "stickiness" of the interface or, put differently, the pull-off force experienced by the atomic force microscopy (AFM) tip during retraction). After the assembly, the NPs can release a previously loaded cargo of surfactant molecules, which then facilitate the formation of a much finer oil-water emulsion. As a proof of concept, we demonstrate the release of octadecyl amine, ODA, that has been incorporated into the NPs prior to the assembly. The release of ODA causes the NPs to detach from the interface altering the interfacial properties and leads to finer oil droplets. This approach can be exploited in applications in several fields ranging from pharmaceutical and cosmetics to hydrocarbon recovery and oil-spill remediation, where a targeted and controlled release of surfactants is wanted.

Rational effect of CuSe2 phase with octadecyl amine modified reduced graphene composite for dual-mode sensing of environmental hazardous anthelminthic drug in aquatic and biological samples

The increasing usage of antihelminthic drug mebendazole (MEB) in humans and livestock poses serious threat and is considered a significant environmental pollutant. Hence, monitoring the MEB residues in environmental samples, and human fluids is essential to decrease the ecological risk and improve the health of humans. In this work, copper selenide (CuSe2) nano/microspheres were hydrothermally synthesized and ultrasonically treated with rGO surface modified with ODA alkyl amine (rGO-ODA). The optical, structural, morphological, and functional analysis were performed which revealed the CuSe2 in marcasite phase, orthorhombic pattern with Pnnm space group, and substantial composite formation. The morphological studies revealed sphere structure of the CuSe2 and wrinkled sheets of rGO-ODA. A sensor that detects MEB using the cyclic voltammetry (CV), differential pulse voltammetry (DPV) and UV-Vis absorbance techniques was developed. For DPV analysis, the sensor exhibited a very low value for limit of detection 13.55 nM and a sensitivity of 9.4871 μA M−1cm−2. For UV-Vis, the sensor demonstrated a very low limit of detection 22.3 nM. The use of this sensor was validated in real-time analysis with aquatic and biological real samples. The results suggested > 90% of analyte recovery and enhanced efficiency for MEB detection with a potential for commercialization in future.

Two-Dimensional Layered Organic-Inorganic Hybrid Perovskite Thin-Film Fabrication by Langmuir-Blodgett and Intercalation Techniques.

We demonstrate the formation of a well-organized thin film of two-dimensional (2D) layered (C18H37NH3)2PbI4 hybrid perovskite by immersing octadecyl amine (ODA) Langmuir-Blodgett (LB) films in an aqueous solution of PbI2/HI. The immersed films exhibit a sharp absorption band at 486 nm (2.55 eV), which is assigned to the excitonic absorption. The film exhibits a bright green emission under ultraviolet light at room temperature. The photoluminescence spectrum has a distinct peak at 497 nm (2.49 eV) and is a mirror image of the absorption spectrum. X-ray diffraction (XRD) analyses reveal that the film has a bilayer-like structure with a d-spacing of 6.4 nm, which is equal to that of a (C18H37NH3)2PbI4 perovskite single crystal with a quantum well (QW) structure. Only intense peaks of the (0 0 l) (l = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24) reflections are observed in the out-of-plane XRD pattern, indicating that the c axis is vertically oriented with respect to the substrate surface, and the orientational order is remarkably high. Fourier transform infrared spectroscopy reveals that the ODA molecules are protonated in the PbI2/HI solution. These results suggest that the nitrogen atoms of the ODA molecules in the film are protonated in the PbI2/HI solution, and then, inorganic layers of the PbI6 octahedra are intercalated in the alkyl ammonium film to neutralize the positive charge and form a QW structure. Fluorescence microscopy observation reveals that the 2D layered (C18H37NH3)2PbI4 film has a relatively uniform surface, reflecting the well-organized layered structure of the base material (ODA LB film). Because the intercalation process can be applied to various metal cations and halogen anions, we believe that the proposed technique will aid in the development of highly efficient 2D layered organic-inorganic hybrid perovskite materials.

Hydrophobization of nanodiamond for polypropylene nanocomposites

Purified and de-aggregated nanodiamonds (ND) synthesized by detonation of explosives provide high surface to volume ratio and unique modification opportunities of their surface groups. In general, ND possesses polar groups, therefore, easily forms agglomerates in non-polar polymer matrix. In this study, the effects of hydrophobization of ND on the structure and the properties of polypropylene (PP) nanocomposites were investigated. Long alkyl chains of octadecyl amine (ODA) were introduced on the surface of ND with the substitution ratio of 68 %. The structural study showed that the dispersibility of ND was remarkably improved by the hydrophobization so that the PP/ND-ODA nanocomposites showed higher transparency than that of the PP/ND nanocomposites. The increased crystallinity of PP in the nanocomposites indicates that ND and ND-ODA acted as crystallization nuclei in the nanocomposites. As for the mechanical properties, the increased Young's modulus of PP/ND nanocomposites was further increased by the addition of ND-ODA. The Young's modulus of the nanocomposites with 0.5 wt% ND-ODA was 64 % higher than that of PP. The strong reinforcement effects also appeared as high heat resistances of the nanocomposites.

Quantum Dot loaded BQCA‐Octadecylamine conjugate nanosystems for theranostic applications in Alzheimer’s Disease.

AbstractBackgroundAlzheimer’s Disease (AD) is one of the most common types of dementias in the world and is characterized by progressive, irreversible neurodegeneration. Benzyl quinolone carboxylic acid was shown to have beneficial in management of AD. The current challenge with BQCA is its low brain half‐life, permeability and rapid elimination. The above challenge can be answered by formulating lipid drug conjugates of BQCA, with octadecyl amine (BQCA‐ODA). Quantum dots (QDs) with their unique optical properties, with high sensitivity and stability emerging as theranostic agents in several neurodegenerative diseases. Hypothesizing the co‐delivery of QDs and BQCA for the effective treatment of AD, in the present study we have formulated lipid nano carriers loaded with quantum dots (QDs) surface modified with Polysorbate 80, called PS80‐QD‐BQCA‐ODA‐NPs, for integrating imaging and therapy for effective management of AD.MethodBQCA was conjugated to Octadecyl amine (ODA), to form BQCA‐ODA LDC conjugate. The amphiphilic nature of the BQCA‐ODA conjugate allows the formation of self‐assembled nanoparticles. Here, we have employed solvent injection method followed by sonication, while addition of QDs in the organic phase and P80 in the aqueous phase to form PS80‐QD‐BQCA‐ODA‐NPs . The optimized formulation was evaluated for physicochemical properties (particle size, zeta potential and polydispersity index) surface morphology and in vitro drug release. The in vitro biocompatibility of the PS80‐QD‐BQCA‐ODA‐NPs was assessed on RBC and SHSY‐5Y cell lines. Further the application of PS80‐QD‐BQCA‐ODA‐NPs was assessed by in vivo imaging and behavioural studies on STZ induced mice models of AD.ResultThe formation of BQCA‐ODA conjugate formation was confirmed 13C‐NMR, 1H‐NMR, LC‐MS. The optimized PS80‐QD‐BQCA‐ODA‐NPs were found to have a near spherical shape with a particle size (PS) of 152.62 ± 1.82 nm, zeta potential (ZP) of 18.59 ± 0.56 mV and polydispersity index (PDI) of 0.214±0.08. PS80‐QD‐BQCA‐ODA‐NPs. The NPs shown improved brain permeability, with greater fluorescence intensity in mouse brains when compared to free QDs. In the in vivo efficiency studies PS80‐QD‐BQCA‐ODA‐NPs shown a significant improvement in memory in mice models.ConclusionThe PS80‐QD‐BQCA‐ODA‐NPs nanomedicine was successfully prepared, thoroughly characterized and has shown theronostic benefits in AD mice models.

Building optimal SEI through control of morphology and chemical composition for high-performance lithium-ion batteries

Recently, SiOx has attracted much attention as a promising anode material for high energy density lithium-ion batteries due to its high specific capacity. However, their long-term durability and storage performance is comparatively poor because of the continuous solid-electrolyte-interphase (SEI) growth. Until now, strategies to effectively improve cycling performance and rate capability by tailored SEIs remain largely unclear, especially in SiOx anodes. Here, we propose an optimal SEI with a unique morphology and chemical composition that are favorable to facilitate the transport of Li ions during the cycles. At first, we fabricated a pillar-type SEI using nanodiamond (ND) additives on the Ti-doped SiOx@C (Ti-SiOx@C) electrode, and the results demonstrated a significant improvement in the capacity retention in the full cell. Meanwhile, we prepared inorganic Li-N and LiF-rich SEIs with high ionic conductivity using octadecylamine (ODA) additives. Based on these results, we constructed the nanoscale pillar structure and inorganic Li-N and LiF-rich SEI with stable and superior ionic conductivity on the Ti-SiOx@C electrode using ND and ODA additives. As a result, the NCM-811||Ti-SiOx@C full cell with ND and ODA additives exhibits superior capacity retention of 91.0% at 1C after 500 cycles compared to the full cell with the baseline electrolyte (58.4%).

Improvement in Migration Resistance of Hydroxyl-Terminated Polybutadiene (HTPB) Liners by Using Graphene Barriers.

The excessive migration of plasticizers leads to debonding and cracking of a liner, which can compromise the safety of a solid propellant. Graphene oxide (GO), with a laminar structure as a filler, can effectively reduce the migration of plasticizers. In this study, we modified GO using toluene diisocyanate (TDI). The cross-link density of the substrate was increased by grafting isocyanate groups to obtain a denser liner for the purpose of preventing plasticizer migration. We also used octadecylamine (ODA) to modify GO by grafting negatively charged amide groups on the GO surface. The electrostatic repulsive effect of the amide group on the plasticizer molecules was used to prevent plasticizer migration. Two modified GOs were filled into the hydroxyl-terminated polybutadiene to prepare two composite liners. We then investigated the migration resistance and migration kinetics of each modified liner using the dipping method. In addition, we explored the mechanical properties of each modified liner. Compared with the original liner, the anti-migration and mechanical properties of the modified composite liners were significantly improved. Among them, the TDI-modified liner had the most obvious improvement in migration resistance, while the ODA-modified liner had the greatest improvement in bonding properties. All types of liners met the requirements of the current propellant systems. This study provides an effective reference for improving the migration resistance and bonding properties of the composite liner.

Disentangle a Complex MALDI TOF Mass Spectrum of Polyethylene Glycols into Three Separate Spectra via Selective Formation of Protonated Ions and Sodium or Potassium Adducts.

In MALDI TOF MS analysis, complicated mass spectra can usually be recorded for polymers with high affinities to protons and alkali metal ions. For these polymers, protonated ions and sodium and potassium adducts can often be formed concomitantly. By distributing these ions into three separate spectra of protonated ions, sodium adducts, and potassium adducts, significantly simplified spectra can be acquired. Mass spectra consisting of only sodium or potassium adducts can often be obtained by simply adding sodium salt and potassium salt, respectively. We report here a method to selectively generate protonated ions. A polyethylene glycol (PEG) sample with amino end groups was selected as the model polymer and α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix. Octadecylamine (ODA) or a mixture of a tetrabutylammonium (TBA) salt and an ammonium salt was used as the co-matrix to inhibit the release of sodium and potassium ions and their related adducts into the MALDI gas phase plume. By depositing the polymer sample on top of a preloaded layer of CHCA with a co-matrix, the generation of Na+ and K+ adducts is suppressed, while [ODA + H]+ and NH4+ released from the preloaded matrix layer can serve as protonation reagents to protonate the polymer molecules via proton transfer reactions. It is clearly demonstrated that disentangling a complex mass spectrum filled densely with various series of ions into three separate spectra, with each one consisting of only one type of ions, allows unambiguous identification of mass peaks and greatly helps the interpretation of MS results.

Study on the enhancement mechanism of luminescent performance of Ag structures on the surface of nano-giant topological luminophor

Y2O3:Eu3++Octadecylamine(ODA)+Dodecylamine(DDA)+Ag giant topological luminophor with a gradient porous structure provides a new thought and approach to greatly improve the luminescent performance of rare-earth-doped nanocomposites phosphors. However, the enhancement mechanism of Ag topological structure, during process of synergistic enhancement, has not been clearly demonstrated and verified by simulation. Based on the quantum size effect of nanomaterials, a nano-giant topological luminophor Y2O3:Eu3++ODA+DDA+Ag was synthesized by solvothermal method in this paper. The experimental results show that the luminescence intensity of Y2O3:Eu3++ODA+DDA+Ag is increased by a substantial improvement of about 700% than that of nano Y2O3:Eu3+ luminophor under the same test conditions, in the synergy mechanism of Ag topological structures and the gradient porous which composed of differently sized pores, with Ag structures accounting for about 45% of the enhancement. On the basis of density functional calculations, the absorption of representative Ag nanoparticles (NPs) in the visible light region(200–900 nm) and its influence on the local electric field around NPs were calculated in this paper. The finite difference time domain simulation results suggested that the surface plasmon resonance of the Ag NPs sharply enhanced the radiative transition of samples. Photoluminescence and electroluminescence experimental results verified the enhancement mechanism of Y2O3:Eu3++ODA+DDA+Ag and the existing form of the Ag NPs. The recombination luminescence induced by the Ag topological structures composed of Ag NPs on the surface of the sample is a crucial part in enhancing the luminescent performance.