Octadecylamine Research Articles

Non-covalent functionalized graphene oxide (GO) adsorbent with an organic gelator for co-adsorption of dye, endocrine-disruptor, pharmaceutical and metal ion

The two-component organic gelator 1-OA (tetrazolyl derivative (1) and octadecylamine (OA)) functionalized graphene oxide (GO) composite was fabricated via non-covalent interactions as a super adsorbent GO/1-OA, which displayed unprecedented adsorption capacity for different pollutants (dyes, endocrine-disruptor, pharmaceutical and metal ion). 1-OA played certain roles in the adsorption process: (1) to stabilize the super adsorbent GO/1-OA by non-covalent forces; (2) to endow the adsorbent with synergistic non-covalent interactions as active sites not only to remove various pollutants in their single system, but also to simultaneous co-adsorb their binary, ternary and quaternary pollutants mixture; (3) to provide GO/1-OA with hydrophobic effect, enabling it can be more easily separated and collected than conventional adsorbent via standing without any filtration or centrifugation. More importantly, the regeneration and reuse of the adsorbent was achieved by simply washing the pollutant off with ethanol.

Mussel-Inspired Polydopamine as a Green, Efficient, and Stable Platform to Functionalize Bamboo Fiber with Amino-Terminated Alkyl for High Performance Poly(butylene succinate) Composites.

A new and eco-friendly mussel-inspired surface modification pathway for bamboo fiber (BF) is presented in this study. The self-assembly polydopamine (PDA) coating can firmly adhere on BF surface, which also serves as a bridge to graft octadecylamine (ODA) for hydrophobic surface preparation. The as-formed PDA/ODA hybrid layer could supply abundant hydrophobic long-chain alkyls groups and generated a marked increase in BF surface roughness and a marked decrease in surface free energy. These changes provided advantages to improve fiber–matrix interfacial adhesion and wettability. Consequently, high performance was achieved by incorporating the hybrid modified BF into the polybutylene succinate (PBS) matrix. The resultant composite exhibited excellent mechanical properties, particularly tensile strength, which markedly increased by 77.2%. Meanwhile, considerable high water resistance with an absorption rate as low as 5.63% was also achieved. The gratifying macro-performance was primarily attributed to the excellent interfacial adhesion attained by hydrogen bonding and physical intertwining between the PDA/ODA coating on the BF and the PBS matrix, which was further determined by fracture morphology observations and dynamic mechanical analysis. Owing to the superior adhesive capacity of PDA, this mussel-inspired surface modification method may result in wide-ranging applications in polymer composites and be adapted to all natural fibers.

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Abstract“Unprotected” Pt nanocrystals were modified with triphenylphosphine (PPh3), octadecylamine (ODA), poly(vinylpyrrolidone) (PVP), poly(vinyl alcohol) (PVA), and dodecanethiol (DT) to investigate the effect of protective agents on the intrinsic catalytic property of Pt nanocrystals. By evaluating the catalytic performance of these model catalysts for the hydrogenation of para‐chloronitrobenzene (p‐CNB), it was found that direct or indirect interaction between nanocrystals and protective agents imposed a great impact on the catalytic performance of the nanocrystals. Protective agents with different electron‐donating ability (PPh3, ODA, PVP, and PVA) directly altered surface electronic state of Pt nanocrystals to bring the surface Pt atoms into an electron‐rich state, which would exert influence on the hydrogenation course by changing the adsorption and the reactivity of reactant, intermediates, and products. In contrast, DT exerted an indirect influence on the Pt nanocrystals. The coordinated Pt atoms were oxidized by DT to generate cationic Pt species on the surface of nanocrystals, and the cationic species would simultaneously improve the hydrogenation rate and selectivity to para‐chloroaniline by polarizing the N=O bond in the −NO2 group of p‐CNB and altering the electronic state of Pt nanocrystals, respectively. This work provided further insights into nanocatalysis, which is helpful for further design and application of highly efficient nanocrystal catalysts.

Highly-efficient organic light-emitting devices based on poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine:octadecylamine-graphene quantum dots

Abstract Organic light-emitting devices (OLEDs) with a poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (poly-TPD):octadecylamine (ODA)-graphene quantum dots (GQDs) hole transport layer (HTL) were fabricated to enhance their efficiency. Photoluminescence (PL) and PL excitation spectra showed that the optical energy bandgap of the ODA-GQDs was 2.7 eV, and ultraviolet photoelectron spectroscopy spectra demonstrated that the edge of the highest occupied molecular orbital of the ODA-GQDs was 5.3 eV below the Fermi level. While the operating voltage of the OLEDs with a PVK:ODA-GQD (9.77 V, 0.25 wt%) HTL at 10 mA/cm2 was 0.8 V lower than that of the OLEDs with a poly-TPD HTL (10.57 V), their current efficiency was larger by more than 20% than that of the OLEDs with poly-TPD (32.88 cd/A) due to an increase in the number of holes injected from the ITO to the HTL. The number of injected holes was increased due to a reduction of the energy barrier and an increase in the conductivity.

Controlled formation of Ag2S/Ag Janus nanoparticles using alkylamine as reductant surfactants

Exploiting the formation mechanism of multicomponent nanomaterials will enable the control of their components or morphologies to enhance their performance for a given application. Herein, we demonstrated a facile controlled synthetic approach to Ag2S/Ag janus nanoparticles through thermal decomposition of single-source precursor silver diethyldithiocarbamate, in which the formation of the heterodimers was determined by the reductant surfactant of octadecylamine. Only if the ratio of octadecylamine (ODA) and oleic acid (OA) was equal or larger than 2:1, this thermal decomposition resulted in the successful formation of janus Ag2S/Ag nanoparticles, which is different from the situation that less ODA led to the formation of Ag2S single component nanoparticles. Dynamic growth results also indicated that the Ag2S/Ag heterodimer structure formed in the nucleation stage. The as-prepared Ag2S/Ag Janus nanoparticles exhibited continuous adsorption window in UV–vis-NIR region and emitted NIR fluorescence at 980 nm. Meanwhile, these nanoparticles showed excellent catalytical degradation activity for methyl blue, which is promising for organic catalysis and pollutant removal application.

Understanding the Inhibition Mechanism of a Supramolecular Complex as the Corrosion Inhibitor for Mild Steel in the Condensate Water

This work attempted to elucidate the corrosion inhibition mechanism of a supramolecular complex formed between β-cyclodextrin (β-CD) and octadecylamine (ODA) for mild steel in the condensate water. Molecular mechanics simulation was applied to determine the energy favored configuration of the complex and the possible orientation of ODA inside the β-CD cavity. Based on the results of gravimetric measurements, thermodynamics parameters for the adsorption process were calculated through Arrhenius and transition state equations. Scanning electron microscopy and X-ray photo electron spectroscopy were used for surface characterization. Density functional theory calculations (Mulliken charges and molecular electrostatic potential plot) were performed to clarify the adsorption mechanism of β-CD/ODA complex on the steel surface. It was found that four possible configurations of β-CD/ODA complex might be concurrent in the supramolecular system with the stable state in the aqueous solution. ODA molecules could break away from the β-CD cavity and chemically adsorbed on the metal surface, which obeyed the Langmuir adsorption isotherm. The inherent molecular electrostatic properties resulted in the tilted adsorption of ODA.

Biocidal Activities of a New Type of Polysaccharide (Extract from Egyptian Aloe Vera)-Based Cationic Schiff Bases Surfactant and Their Metal Complexes

Five series of cationic polysaccharide Schiff bases surfactant [AQ_10-18] were synthesized by the reaction between different five Schiff bases (which prepared by condensation of fatty amine namely: decyl, dodecyl, tetradecyl, hexadecyl and octadecyl amine and 4-pyridine carboxaldehyde) and polysaccharide sulfate as quaternizing agent. Also, their complexes with different transition metals including Ni²⁺, Co²⁺, Cu²⁺ and Fe³⁺ were synthesized. The chemical structures of these surfactants were confirmed using elemental analysis, FTIR spectra, UV spectra, 1H-NMR and atomic absorption spectroscopy. The studied surfactants were evaluated as antimicrobial agents against pathogenic and sulfate reducing bacteria using inhibition zone diameters. The synthesized cationic polysaccharide Schiff bases surfactant showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative, yeast and fungi. The effect of the structure of these cationic surfactants and their metal complexes of Ni²⁺, Co²⁺, Cu²⁺ and Fe³⁺ on the cell membrane is discussed as well as their potent action on the targeted bacteria, yeast and fungi.

Effect of nano clay platelets on the hybrid monolayer of a cationic oxazine dye: In-situ Brewster Angle Microscopic (BAM) study

The present work investigates the adsorption of a cationic oxazine dye, cresyl violate acetate (CVA), into the anionic Laponite nano clay platelets through electrostatic interaction. The adsorption resulted in the formation of Clay-CVA hybrid molecules at the air water interface. CVA tagged nano clay platelets were further adsorbed onto a cationic surfactant, Octadecylamine (ODA), matrix at the air water interface and as a consequence a stable and almost uniform ODA-Clay-CVA hybrid monolayer was formed. The organization of hybrid molecules in Langmuir trough was changed under monolayer compression resulting in the formation of different sized and shaped domain structures. Surface pressure – area per molecule (π-A) isotherm studies and in-situ Brewster angle microscopic (BAM) studies were employed in this investigation to explore the monolayer chracteristics.

Pharmaceutical crystallization in surface-modified nanocellulose organogels.

A significant research focus in the pharmaceutical industry is on methods to improve drug uptake into the body by increased dissolution of poorly water soluble active pharmaceutical ingredients (APIs) or sustained drug release behavior, which results in higher overall uptake. Production of higher energy, higher solubility polymorphs is one approach to address this problem. Here we utilize natural materials, cellulose nanocrystals (CNCs), that have a high surface area covered with readily-modified hydroxyl groups to form organogels that promote API crystallization into polymorphs that differ from the as-received materials. We form the gels by oxidizing the CNCs and mixing them with an amine-containing surfactant, octadecylamine (ODA) in dimethylsulfoxide (DMSO) and we optimize the composition and preparation conditions for these gels. The APIs, sulfamethoxazole, sulfapyridine, and sulfamerazine, are added to the mixture prior to the gelation step and are expected to localize in the solvophobic regions of the physical gel and crystallize. We found that sulfamethoxazle recovered from the gels is in the amorphous state, while sulfapyridine crystallizes into a mixture of forms I, III and IV, and sulfamerazine crystallizes into forms I and II, which are different from the as-received materials. This system shows promise for rational design of nanocellulose organogel supports for heterogeneous crystallization of pharmaceutical materials with desired polymorphs.

Facile one-step synthesis of Cu2O@Cu sub-microspheres composites as anode materials for lithium ion batteries

Cu2O@Cu sub-microspheres composites with a narrow particle size distribution from 300 to 500nm was successfully fabricated by one-step synthesis through the direct thermal decomposition of copper nitrate (Cu(NO3)2) in octadecylamine (ODA) solvent. As anode materials for lithium ion batteries, the Cu2O@Cu composites obviously possess high specific capacity, excellent cyclic stability and rate capability. The coulombic efficiency is about 84% in the 1st cycle and increases significantly up to 97.8% during successive cycles at various current densities. Even under a high current density of 500mAg−1, the discharge capacity of Cu2O@Cu composites remains up to 200mAhg−1. The excellent electrochemical properties are ascribed to the synergistic effect between high electronic conductivity and volume-buffering capacity of metallic copper composited with Cu2O.

Microdiamond/PLA composites with enhanced thermal conductivity through improving filler/matrix interface compatibility

Polylactic acid (PLA)-based composites filled with 20 or 50μm-diameter microdiamond are synthesized by hot pressing. Through improving the interface compatibility between the filler and the matrix enabled by octadecylamine (ODA) coating on the microdiamond particles, the maximum thermal conductivity of the composites is 2.22Wm−1K−1, which is a ~10-fold increase in comparison with that of pure PLA. According to the analysis on the glass transmission of the composites and the surface chemistry of the fillers using DSC, FI-IR, and Raman microscopy, it is found out that ODA is connected with the OH group on the microdiamond surface through hydrogen bonding and an interfacial structure of PLA/ODA/microdiamond is formed. Thus, the interfacial thermal transport between PLA and microdiamond is significantly improved, leading to the enhancement of the thermal conductivity of the composites. Our work presents a simple method to modify the surface chemistry of microdiamond and to improve the interface compatibility between microdiamond and PLA. The microdiamond/PLA composites with large thermal conductivity are promising thermal management materials used for modern electronic products.

Enhanced enzymatic degradation in nanocomposites of various organically-modified layered zinc phenylphosphonates and poly (butylene succinate-co-adipate)

In this work, two long-chain alkylamines, dodecylamine (DDA) and octadecylamine (ODA), intercalated with layered zinc phenylphosphonates (PPZns) were prepared using a simple chemical intercalation method. Both biocompatible poly(butylene succinate-co-adipate) (PBSA)/organically-modified PPZn nanocomposites fabricated by a melt-mixing technique have been characterized by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). These results indicated that the stacking layers of the ODA-PPZn in the PBSA matrix were fully/partially exfoliated and the intercalated PBSA/DDA-PPZn nanocomposites were formed. Enzymatic degradation tests using Lipase from Pseudomonas sp. as the enzyme was investigated. The weight loss of PBSA increases with an increase in the content of organically-modified PPZn. The degradation rate of all samples varied in the order PBSA/ODA-PPZn nanocomposites > PBSA/DDA-PPZn nanocomposites > neat PBSA. This result is probably due to the lowest degree of crystallinity for PBSA/ODA-PPZn nanocomposites. The degradation behavior of the neat PBSA belongs to exo-type hydrolysis activity due to the degradation starts from both ends of the polymer chains.

Corrosion Behavior of Carbon Steel Coated with Octadecylamine in the Secondary Circuit of a Pressurized Water Reactor

Corrosion and particle deposition in the secondary circuits of pressurized water reactors can be mitigated by alternative water chemistries featuring film-forming amines. In the present work, the corrosion of carbon steel in secondary side water with or without octadecylamine (ODA) is studied by in situ electrochemical impedance spectroscopy, combined with weight loss/gain measurements, scanning electron microscopy and glow-discharge optical emission spectroscopy. The impedance spectra are interpreted using the mixed-conduction model to extract kinetic parameters of oxide growth and metal dissolution through it. From the experimental results, it can be concluded that ODA addition reduces the corrosion rate of both fresh and pre-oxidized carbon steel in secondary circuit significantly by slowing down both interfacial reactions and transport through the oxide layer.

Fabrication of functionalized graphene oxide/maleic anhydride grafted polypropylene composite film with excellent gas barrier and anticorrosion properties

The octadecylamine (ODA) modified graphene oxide (mGO-ODA)/maleic anhydride grafted polypropylene (MAPP) composites (mGO-ODA/MAPP) were prepared and applied successfully as gas barrier and corrosion protection coating materials for the first time. The hydrophobic mGO-ODA sheets showed improved solubility in non-polar solvents with molar absorptivity was found to be 36mLmg−1cm−1 in ethylcyclohexane. FTIR analysis confirmed that mGO-ODA chemically interacts with MAPP. The mGO-ODA nanosheets were well exfoliated and dispersed in the MAPP matrix as confirmed by XRD analysis. The mGO-ODA/MAPP composites were coated on modified nylon sheets by a spray coating method, and the gas transmission rates (GTRs) of H2 and O2 were tested for these coated films. Cross-sectional FESEM showed the excellent attachment of these composite with the nylon film. The 60% mGO-ODA/MAPP-coated nylon film exhibited 93% and 112% improvement in elastic modulus values than the MAPP-coated and pure nylon films, respectively. Besides, 60% mGO-ODA/MAPP exhibited 94.1% and 95.0% reduction for H2GTR and O2GTR, respectively, compared to the pure nylon film. In addition, mGO-ODA/MAPP coated steel substrate exhibited excellent anticorrosion performance. The corrosion inhibition efficiency and corrosion rate were calculated to be 99.15% and 2.26 × 10−3mm/year, respectively, for 60% mGO-ODA/MAPP.

Poly (N-acryloxysuccinimide-co-ethylene glycol dimethacrylate) precursor monolith and its post polymerization modification with alkyl ligands, trypsin and lectins for reversed-phase chromatography, miniaturized enzyme reactors and lectin affinity chromatography, respectively.

This investigation was aimed at introducing a monolithic precursor that can be conveniently grafted with the desired chromatographic ligand via the process of post polymerization modification (PPM). The precursor was obtained by the in-situ polymerization of N-acryloxysuccinimide (NAS) and ethylene glycol dimethacrylate (EDMA) in a narrow bore stainless steel column of 1mm i.d. yielding a poly(NAS-co-EDMA) monolithic column designated as the poly(NAS-co-EDMA) monolith (NASM) column. In a first PPM, the NASM column was bonded with octadecyl (OD) ligands yielding a nonpolar NASM-OD column that proved useful for reversed phase chromatography (RPC) of proteins in gradient elution at increasing %ACN in the mobile phase. NASM-OD resulted from the reaction between the N-hydroxysuccinimide of NASM with octadecyl amine. In a second PPM, NASM was surface immobilized with trypsin generating a proteolytic narrow bore enzyme reactor called NASM-trypsin immobilized enzyme reactor (IMER) that permitted the online digestion of proteins in a 20-min single pass through the IMER incorporated in a setup equipped with a short RPC column to achieve simultaneously a peptide tryptic map. This constituted a rapid turnover whereby ∼95% of the protein was hydrolyzed by the immobilized trypsin. In a third PPM, the NASM column was surface immobilized with three different lectins (LCA, Con A and RCA) having complementary affinities toward serum glycoproteins thus permitting the capture of a wide range of glycoproteins/glycoforms. The three NASM-lectin columns when operated in a tandem format led to assessing the level of the various glycoforms in human serum via LC-MS/MS analysis of the captured protein fractions by each NASM-lectin column.

Crossover magnetic amphiprotic catalysts for oil/water separation, the purification of aqueous and non-aqueous pollutants, and organic synthesis

Magnetic amphiprotic catalysts (MACs) were synthesized by coating magnetic nanoparticles (MNPs) stepwise with polydopamine (Pdop), a polyethyleneimine (PEI) brush, octadecylamine (ODA), and Au. The amphiprotic characteristics of the MACs were tuned by varying the portions of the hydrophilic and hydrophobic moieties. The MACs normally dispersed in the hydrophobic layer but were forced into water to catalytically decompose aqueous pollutants upon the application of a magnetic field. When the magnetic field was turned off, the MACs naturally returned to the hydrophobic layer and catalytically decomposed non-aqueous pollutants. Next, the purified oil was readily separated from the oil/water mixture by using the magnetic field because the MACs absorbed oil. Oil-in-water and water-in-oil wastewater emulsions containing aqueous and non-aqueous pollutants, respectively, were also purified and separated into pure oil and water. A series of wastewater purification steps, including oil/water separation and the decomposition of aqueous and non-aqueous pollutants in both phases, was performed by in situ and continuous processes using the MACs. The MACs also performed catalytic organic reactions in organic solvents.

Octadecylamine-Grafted Graphene Oxide Helps the Dispersion of Carbon Nanotubes in Ethylene Vinyl Acetate.

In this paper, the dispersion of carbon nanotube (CNT) in ethylene vinyl acetate (EVA) is demonstrated to be significantly improved by the addition of octadecylamine (ODA)-grafted graphene oxide (GO) (GO–ODA). Compared to the CNT/EVA composite, the resultant GO–ODA/CNT/EVA (G–CNT/EVA) composite shows simultaneous increases in tensile strength, Young’s modulus and elongation at break. Notably, the elongation at break of the G–CNT/EVA composite still maintains a relatively high value of 1268% at 2.0 wt % CNT content, which is more than 1.6 times higher than that of CNT/EVA composite (783%). This should be attributed to the homogeneous dispersion of CNT as well as the strong interfacial interaction between CNT and EVA originating from the solubilization effect of GO–ODA. Additionally, the G–CNT/EVA composites exhibit superior electrical conductivity at low CNT contents but inferior value at high CNT contents, compared to that for the CNT/EVA composite, which depends on the balance of CNT dispersion and the preservation of insulating GO–ODA. Our strategy provides a new pathway to prepare high performance polymer composites with well-dispersed CNT.

The shell thickness and surface passivation dependence of fluorescence decay kinetics in CdSe/ZnS core-shell and CdSe core colloidal quantum dots

Femtoseconds, ultrafast, time-resolved, fluorescence upconversion spectroscopy was utilized to investigate the photo-induced emission decay dynamics of CdSe and CdSe/ZnS colloidal quantum dots whose surfaces were stabilized with octadecyl amine (ODA). The studies focused on understanding the influence of the surface stabilizing group on the fluorescence decay dynamics of CdSe and CdSe/ZnS and the effect of shell thickness on the photo-physical properties of core-shell quantum dots. The Core-shell materials showed excellent photostability, longer rise times, and lengthy decay times.

Synergistic inhibition effects of octadecylamine and tetradecyl trimethyl ammonium bromide on carbon steel corrosion in the H2S and CO2 brine solution

The corrosion inhibition performances of octadecylamine (OCT) and tetradecyl trimethyl ammonium bromide (TTAB) for carbon steels in H2S and CO2 brine solution were investigated by weight loss, potentiodynamic polarization, molecular dynamic simulation and XPS analysis. TTAB showed better inhibition effects on H2S and CO2 induced corrosion than OCT. Synergistic corrosion inhibition effect was found between OCT and TTAB with proper mass ratios and the best inhibition performance was achieved with 10mgL−1 OCT and 20mgL −1 TTAB. The synergism was correlative to the fractional free volume of the inhibitor film of OCT and TTAB.

Effect of sodium hydroxide solution as polymerization solvent and activator on structural, mechanical and antibacterial properties of PNIPAAm and P(NIPAAm–clay) hydrogels

Poly(N‐isopropylacrylamide) (PNIPAAm) and its composite hydrogels were synthesized by free‐radical polymerizations in NaOH solutions (0.1, 0.2 N). Laponite (LP), Montmorillonite (MMT) and ODA(octadecylamine)‐MMT were used as inorganic multicrosslinkers while BIS was chosen as conventional crosslinker. All polymerizations were initiated with KPS alone. The effects of two different concentrations of NaOH‐KPS redox pair and long reaction times (1w and 2w) at 25°C on structural and mechanical properties, antibacterial and haemolytic activities of the modified hydrogels were studied by conductometric titrations, FTIR, XRD, EDX, compression, inhibition zone and haemolysis tests. Their homogenities, compressive moduli at 37°C, antibacterial activities and blood compatibilities increased with increasing reaction time and NaOH concentration. POLYM. COMPOS., 39:E386–E406, 2018. © 2017 Society of Plastics Engineers