Long-chain Alkylamines Research Articles

Synthesis and characterization of a series of amidine-based switch surfactants: toward environmental surface-active materials

A series of newly structured two-tailed cationic surfactants were synthesized via a carbonyl amine condensation reaction aimed at reducing the bioaccumulation of conventional surfactants while maintaining their excellent surface properties. Long-chain alkyl amine compounds can be reversibly converted into charged surfactants through CO2/H2O treatment and an alkyl chain length of between C8 and C12. The structures were characterized by IR,1H NMR and 13C NMR. The main surface activity parameters of the surfactants, containing cmc, γcmc pC20, cmc/С20, Γm and Αmin, were determined. The switching properties of N’-alkyl-N, N-dimethylalkamidine bicarbonate and N, N-dimethyl-N-alkylamidine bicarbonate were demonstrated by investigating their conductivities in solution and carrying out their emulsification-emulsion-breaking experiment.

Recycling of expired cow milk for constructing multifunctional biomass nonfluorinated chromatic paint with superhydrophobicity

Through denaturation and amination of the mixture, consisted of expired cow milk, kaolin and gardenia yellow, in the hot organic solvent that contained alkaline aminosilane coupling agent, then adsorption of diverse acid dyes in the acid condition, thus obtaining active matrixes with different colors. By virtue of the non-catalyzed in-situ reaction among the acrylate groups of pentaerythritol ester compounds and the amino groups of obtained matrixes as well as long-chain alkyl amines, the biomass fluoride-free superhydrophobic doped paints was prepared, however the poor stability was reflected in its anti-wetting coating surface. Furthermore, in order to improve durable superhydrophobicity and multifunctionality of the expired cow milk-based water-repellent paint, the thermally denatured protein, originated from expired cow milk heating, was blended with nanoscale inorganic pigments to accept the before-mentioned procedures of amination and in-situ growth, consequently constructing the multifunctional biomass nonfluorinated chromatic paint with robust superhydrophobic function, moreover its coated fabrics had 155.7° of average contact angle and 1.5° of average sliding angle. Additionally, by only using synergy of complex denaturation and chemical coupling, the expired cow milk could be transformed into UV-photoluminescent nonfluorinated superhydrophobic color paint, the contact angle of such paint-coated fabric was 153.3° and its sliding angle was 2°. Based on the additional function of as-prepared biomass paints, the applications of non-wetted switchable fluorescence imaging as well as photothermal deicing were realized. We believe that the expired cow milk-based multifunctional paints can expand into the fields of outdoor protective textiles, decorative building materials, fluorescent falsification-preventing and ice protection.

Boosting the Carrier Lifetime and Optical Activity of CsPbX3 Nanocrystals through Aromatic Ligand Passivation.

Ligand engineering is crucial for tuning the structural and optoelectronic properties of perovskite nanocrystals (NCs), which also improves their stability. In contrast to the typically used long-chain alkylamine ligands, we successfully introduced an aromatic 1-(p-tolyl)ethylamine (PTEA) ligand to synthesize the CsPbX3 (X = Br or I) NCs. The CsPbI3 and CsPbBr3 NCs demonstrated long carrier lifetimes of ∼877 and 49 ns, respectively, as well as high photoluminescence quantum yields (PLQYs) of ∼99% and 95%, respectively. Furthermore, such NCs realized excellent long-term stability in an ambient atmosphere without obvious degradation over one month. All of these properties were better than the properties of NCs coated with the conventional alkylamine ligands. The high performance of these NCs was discussed with the effective surface passivation by PTEA. Our finding suggests a facile and effective ligand (PTEA) for modulating perovskites, achieving enhancement of both the carrier lifetime and the PLQY.

Narcissus pseudonarcissus L. (Amaryllidaceae) bulb metabolite profiling and biological activities

Various metabolomics approaches have greatly contributed to the study of natural products from medicinal plants. Among thousands of plant species, Narcissus pseudonarcissus L. (Amaryllidaceae) is reputed for its ornamental, industrial, and medicinal applications. This plant is also used traditionally for microbial infections, inflammations, skin complaints, and cancers. Long ago, N. pseudonarcissus has gained considerable research interest thanks to its diverse alkaloids that have been widely studied. However, the non-alkaloidal principles and different bioactivities of this plant were poorly deliberated in previous works. Therefore, this work evaluates the biological potential of N. pseudonarcissus bulbs′ total ethanol extract (TEE) and its derived fractions (I‒IV), along with exploring the overlooked non-alkaloidal metabolites of this amaryllid. Overall, GC‒MS-based analysis of the bulbs led to the identification of varied metabolites, e.g., long-chain alkyl amines, alkylbenzenes, long-chain hydrocarbons, fatty acid derivatives, and phenylpropanoids. Most of these phytochemicals are first characterized herein in either the genus Narcissus or the family Amaryllidaceae. Additionally, the acidic EtOAc fraction (II) exhibited the highest scavenging potential of the 2,2′-diphenyl-1-picrylhydrazyl radical and the greatest ferric reducing power, possibly due to its relatively higher contents of phenolics and flavonoids that were also estimated herein. On the other hand, the basic EtOAc fraction (III) exerted the maximum anti-proliferative actions against Caco-2 (colon) and Mcf-7 (breast) tumor cells, while all of the tested fractions were inactive against HepG-2 (liver) cancer cells. Finally, different N. pseudonarcissus fractions demonstrated varied inhibitory activities against a group of pathogenic bacteria and fungi. Among them, fractions II and III were further observed as good synergists with some standard antimicrobial agents, even against some resistant microbial strains. These data could support the reported use of N. pseudonarcissus in traditional medical systems and help widen its future phytochemical and biological prospection.

Amidoamine Oxide Surfactants as Low-Molecular-Weight Hydrogelators: Effect of Methylene Chain Length on Aggregate Structure and Rheological Behavior.

Rheology control is an important issue in many industrial products such as cosmetics and paints. Recently, low-molecular-weight compounds have attracted considerable attention as thickeners/gelators for various solvents; however, there is still a significant need for molecular design guidelines for industrial applications. Amidoamine oxides (AAOs), which are long-chain alkylamine oxides with three amide groups, are surfactants that act as hydrogelators. Here, we show the relationship between the length of methylene chains at four different locations of AAOs, the aggregate structure, the gelation temperature Tgel, and the viscoelasticity of the formed hydrogels. As seen from the results of electron microscopic observations, the aggregate structure (ribbon-like or rod-like) can be controlled by changing the length of methylene chain in the hydrophobic part, the length of methylene chain between the amide and amine oxide groups, and the lengths of methylene chains between amide groups. Furthermore, hydrogels consisting of rod-like aggregates showed significantly higher viscoelasticity than those consisting of ribbon-like aggregates. In other words, it was shown that the gel viscoelasticity could be controlled by changing the methylene chain lengths at four different locations of the AAO.

Oligomeric cationic Gemini surfactants: synthesis, surface activities and rheological properties as thickener

Abstract In this study, three oligomeric cationic Gemini surfactants (Ⅲ1, Ⅲ2, and Ⅲ3) were prepared from different major raw materials, including long-chain alkyl amine (dodecyl amine, tetradecyl amine or cetyl amine), formic acid, formaldehyde, diethyl amine hydrochloride and epichlorohydrin. The synthesis conditions for one of the three surfactants, bis-[2-hydroxy-3-(N,N-dimethyl-N-dodecyl)propyl]dipropylammonium chloride (Ⅲ1), were optimised by orthogonal experiments. The optimum synthesis conditions were: molar ratio of intermediate Ⅱ to intermediate Ⅰ1 = 1.0:2.2, reaction temperature = 85 °C and reaction time = 16 h. The structures of the three prepared compounds were characterised by FTIR and 1H NMR. Their thermal properties were evaluated by thermal gravimetric analysis (TGA). The Geminisurfactants prepared exhibited better surface active properties than conventional single chain cationic surfactants. With increasing carbon chain length from C12 to C16, both CMC and surface tension γ CMC decreased, while the viscosity of the thickening solution prepared with the synthesised oligomeric cationic Gemini surfactants as the main component increased. The optimum thickening formula was: 2.0 wt% Ⅲ3 + 0.8 wt% sodium salicylate (NaSal) + 0.6 wt% KCl. The viscosity of the optimum thickening formulation was 190.4 mPa s. Gemini oligomeric cationic surfactants could be used as thickeners in the production of fracturing fluids, flooding agents and drilling fluids for oil and gas production in oil fields.

Cotton fabrics modified with tannic acid/long-chain alkylamine grafting for oil/water separation

BackgroundsCotton fabrics were modified on surface wettability for efficient oil/water separation. The modification adopted in previous literature are commonly complicated in steps, expensive in chemicals applied, and not environmentally begien in solvents used. ExperimentsThis article applied a novel one-step modification protocol to modified cotton fabrics using tannic acid (TA) grafted via Michael addition/Schiff base reactions with long-chain alkylamines, including 1-tetradecylamine (TDA), 1-hexadecylamine (HDA), and 1-octadecylamine (ODA) with 14, 16 and 18 methyl groups, respectively, were applied in this study for cotton fabrics modification. The TA, an inexpensive natural polyphenol, was adopted for providing excess catechol groups for linking the cotton surface and the alkylamines. The grafting reactions via Michael addition/Schiff base reaction were performed at room temperature and pH 8.5 with catalysts CuSO4/H2O2 for significantly reducing the reaction time needed. ResultsThe chemical analysis confirmed the modification of the cotton fabrics to possess hydrophobic surface, with contact angles for water droplets on the modified surface as 133.3o, 136.0o and 142.9° for TA-TDA, TA-HDA, and TA-ODA cotton fabrics, respectively; and diiodinemethane droplets on the modified surface being 56.0o, 58.8o and 59.3o, respectively. The modified cotton surface has intermediate dispersive component of surface energy (29.0–31.2 mJ/m2) and low polar component (4.2–6.2 mJ/m2), yielding high affinity to oil but low affinity to water. Parametric study revealed that the pH value and reaction time are the most important parameters for the alkylamine grafting reactions, while the reduction of catalyst amount used but still with sufficient modification on cotton fabrics can be achieved. The oil absorption tests with cotton fabrics contacting hexane (top)-water (bottom) layers revealed high hexane adsorption capacity: 0.96, 1.22, 1.25 g hexane/g cotton for TA-TDA, TA-HAD and TA-ODA cotton fabrics, respectively. The absorption tests with cotton fabrics contacting water first for 30 s then hexane for another 30 s had much lower absorption capability of hexane: 0.52, 0.85, 0.87 g hexane/g cotton for TA-TDA, TA-HAD and TA-ODA cotton fabrics, respectively, since water would penetrate the major pores for inhibiting further oil absorption.

An Improved PEG-Linked Solid Support for Minimizing Process-Related Impurities During Solid-Phase Synthesis of DNA and RNA Sequences.

The preparation of controlled pore glass (CPG) supports, functionalized with several hexaethylene glycol spacers, to alleviate the problems associated with the porosity of commercial CPG supports is described in this article. The pore size of CPG restricts the diffusion of reagents to the leader nucleoside embedded in porous supports; this inhibits efficient solid-phase syntheses of DNA and RNA sequences and, by default, the purity of those sequences through formation of a shorter than full-length oligonucleotide. Functionalization of a CPG support with five hexaethylene glycol spacers led to a 42% reduction in process-related impurities contaminating oligonucleotide sequences, compared to that obtained using the commercial long-chain alkylamine (LCAA) CPG support. © 2021 Wiley Periodicals LLC. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Basic Protocol 1: Preparation of the hydroxylated CPG support 3 Basic Protocol 2: Automated preparation of the CPG support 6 Basic Protocol 3: Automated preparation of the poly(hexaethylene glycol)-derived CPG 7 Basic Protocol 4: Automated functionalization of the poly(hexaethylene glycol)-derived CPG support 7 with leader deoxyribo- and ribonucleosides to provide the CPG support 9 Basic Protocol 5: Automated syntheses of DNA and RNA sequences on poly(hexaethylene glycol)-derived CPG support 9 and on a commercial long-chain alkylamine (LCAA) CPG support Support Protocol: Release and deprotection of the DNA and RNA sequences linked to the poly(hexaethylene glycol)-derived CPG support 10 and commercial LCAA-CPG support Basic Protocol 6: Comparative RP-HPLC analyses of crude, fully deprotected DNA or RNA sequences released from the poly(hexaethylene glycol)-derived CPG support 10 and from a commercial LCAA-CPG support.

An expedient process for reducing the formation of process-related impurities during solid-phase synthesis of potential nucleic acid-based drugs

With the intent of mitigating the formation of process-related impurities during solid-phase synthesis of DNA or RNA sequences, a hydroxylated controlled-pore glass support conjugated to three, five or seven hexaethylene glycol spacers was prepared and demonstrated to provide a more efficient and robust synthesis process. Indeed, the use of a support conjugated to five hexaethylene glycol spacers led to a 19% up to 42% reduction of process-related impurities contaminating synthetic nucleic acid sequences, when compared to that obtained from the same DNA/RNA sequences synthesized using a commercial long-chain alkylamine controlled-pore glass support under highly similar conditions.

Inverted devices are catching up

Perovskite solar cells with an inverted configuration hold great promise for multi-junction applications, but their power conversion efficiency is low. Now, a long-chain alkylamine ligand-assisted strategy has been demonstrated to enable an efficiency of 22.34%.

A Thiolactone Strategy for Straightforward Synthesis of Disulfide-Linked Side-Chain-to-Tail Cyclic Peptides Featuring an N-Terminal Modification Handle.

The development of straightforward and versatile peptide cyclisation methods is highly desired to meet the demand for more stable peptide-based drugs. Herein, a new method for the synthesis of side-chain-to-tail cyclic peptides with the simultaneous introduction of an N-terminal handle, based on the introduction of an N-terminal thiolactone building block, is described. A primary amine liberates a homocysteine analogue from the thiolactone building block, which further enables cyclisation of the peptide through disulfide-bond formation with a C-terminal cysteamine. Postcyclisation modification can be achieved by using small bifunctional amines. Alternatively, the synthesis of lipopeptides is demonstrated through direct thiolactone opening with long-chain alkyl amines.

Study of adsorption characteristics of long chain alkyl amine and petroleum sulfonate on silicates by electrokinetic potential, microflotation, FTIR, and AFM analyses

ABSTRACTThe long-chain alkyl amines and petroleum sulfonates are mostly used to remove unwanted minerals from feldspar ores in acidic pHs. In this study, their adsorption characteristics on pure albite and quartz were investigated by electrokinetic potential measurements, microflotation tests, Fourier transform infrared spectroscopy, and atomic force microscopy studies. According to the results, amine had strong influence on zeta potentials of both albite and quartz turning them positive and resulting over 90% flotation recovery at certain pH values. Petroleum sulfonate, on the other hand, was less effective in terms of both zeta potential values and flotation recovery responses of albite. Although albite and quartz had different zeta potentials and flotation recovery responses with each collector, they displayed similar adsorption bands of CH2 group over fingerprint region and adsorption layers with different intensities after being treated with the collectors. However, the adsorption of each collector on the minerals was altered by rinsing with acetone indicating that the interaction of the collectors with albite and quartz surfaces were mostly by Coulombic forces and hydrogen bonding.

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.

Preparation of Robust Superhydrophobic Halloysite Clay Nanotubes via Mussel-Inspired Surface Modification

In this study, a novel and convenient bio-inspired modification strategy was used to create stable superhydrophobic structures on halloysite clay nanotubes (HNTs) surfaces. The polydopamine (PDA) nanoparticles can firmly adhere on HNTs surfaces in a mail environment of pH 8.5 via the oxidative self-polymerization of dopamine and synthesize a rough nano-layer assisted with vitamin M, which provides a catechol functional platform for the secondary reaction to graft hydrophobic long-chain alkylamine for preparation of hierarchical micro/nano structures with superhydrophobic properties. The micromorphology, crystal structure, and surface chemical composition of the resultant superhydrophobic HNTs were characterized by field emission scanning electron (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The as-formed surfaces exhibited outstanding superhydrophobicity with a water contact angle (CA) of 156.3 ± 2.3°, while having little effect on the crystal structures of HNTs. Meanwhile, the resultant HNTs also showed robust stability that can conquer various harsh conditions including strong acidic/alkaline solutions, organic solvents, water boiling, ultrasonic cleaning, and outdoor solar radiation. In addition, the novel HNTs exhibited excellent packaged capabilities of phase change materials (PCMs) for practical application in thermal energy storage, which improved the mass fractions by 22.94% for stearic acid and showed good recyclability. These HNTs also exhibited good oil/water separation ability. Consequently, due to the superior merits of high efficiency, easy operation, and non-toxicity, this bionic surface modification approach may make HNTs have great potentials for extensive applications.

Preparation of Patterned Ultrathin TiO2 Films by Langmuir–Blodgett Method Using Mixed Monolayers of Octadecylamine and 1H,1H-Perfluoro-1-dodecanol

An approach for the preparation of patterned ultrathin TiO2 films is demonstrated by using phase-separated Langmuir monolayers, wherein the mixed monolayer of long-chain alkylamine and perfluoroalcohol is formed on an aqueous subphase containing potassium titanium oxalate, followed by deposition onto a solid substrate as a single-layer Langmuir–Blodgett (LB) film. Atomic force microscope observation of the LB films shows that ring-like TiO2 domains are formed on the surface of the substrate and that the size and shape of the TiO2 domains can be tuned by concentration of spreading solution as well as mixing ratio of the two film materials. Subsequent heat-treatment at 500 °C results in TiO2 films of 1.6 nm in thickness maintaining the ring-like pattern.

N,N-Diethyl-diaminopropane-copper(ii) oxalate self-reducible complex for the solution-based synthesis of copper nanocrystals.

Metal oxalates (C2O42-, ox) have been explored as promising precursors for the direct transformation of their oxalate moieties into metallic or metal oxide crystals via thermal decomposition without the formation of any byproducts due to releasing CO2 gas. The copper(ii) oxalate (Cu(ox)) crystal is a coordination polymer composed of an infinite coordination network with a thermal decomposition temperature around 300 °C; however, their insoluble nature in any solvents and relatively high decomposition temperature do not allow the solution-based syntheses of surface-modified metallic Cu nanocrystals (NCs) in the presence of various surfactants such as long-chain alkylamines and alkylcarboxylates which have been used for increasing the dispersibility of NCs in organic solvents. In this study, the insoluble nature of Cu(ox) is overcome by mixing Cu(ox) crystals and N,N-diethyl-1,3-diaminopropane (dedap) to form a discrete complex, [Cu(ox)(dedap)2], whose structure is determined by X-ray crystallographic analysis. The obtained complex is well soluble in polar solvents and miscible with surfactants. Furthermore, it is decomposed at a moderate temperature of <170 °C with the evolution of CO2 gas; as a result, Cu NCs dispersible in organic solvents have been synthesized in suitable surfactants, such as the mixture of oleic acid, dodecylamine, and octylamine utilized as a reaction solvent. In addition, their potential application of the surface-modified Cu NCs as a conductive-ink has been preliminarily tested. The Cu film sintered at 280 °C exhibits a resistivity of 40 μΩ cm.

Solid-state phase transition induced by ordering of flexible chain alkylamine in N-ethyl-n-butylammonium 3, 5-dinitrobenzoate monohydrate

A new molecule-based compound, N-ethyl-n-butylammonium 3, 5-dinitrobenzoate monohydrate, which undergoes a reversible solid-state phase transition at 197K (Tc), has been successfully constructed based on long-chain alkylamine. Specific heat capacity and differential scanning calorimetry (DSC) measurements confirm that it is first-order phase transition with a 5K thermal hysteresis between heating and cooling scans. Dielectric constants exhibit distinct anomalies around Tc accompanied with step-like responses between low and high dielectric states, which further confirm the phase transition. Variable-temperature single-crystal X-ray diffraction analyses illustrate that the phase transition was elucidated from ordering of the flexible N-ethyl-n-butylammonium cations coupled with reorientational motion of the alkylamine chain.

Enhanced organophilic separations with mixed matrix membranes of polymers of intrinsic microporosity and graphene-like fillers

Organophilic mixed matrix membranes (MMMs) have been fabricated with the polymer of intrinsic microporosity PIM-1 and graphene oxide (GO) derivatives for the recovery of 1-butanol and ethanol from aqueous solutions via pervaporation (PV). Graphene oxide (GO) has been synthesized in solution through a modified Hummers’ method, functionalized with alkylamines, and further reduced. The use of two alkylamines with chains of different lengths, octylamine (OA) and octadecylamine (ODA) −8 and 18 carbons, respectively - has been evaluated and the functionalized GO materials have been used as fillers in MMMs. The membranes have been prepared by casting-solvent evaporation of PIM-1/GO derivative solutions at room temperature, and a range of characterization techniques have been used to interpret their structure and relate it to their separation performance. Electron microscopy has been carried out to determine the morphology of the membranes and the dispersion of the functionalized GO flakes in the polymer matrix. Moreover, the membranes have been characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and contact angle. Separation of alcohol from two binary mixtures composed of ethanol (EtOH)/water and butanol (BtOH)/water, containing 5wt% of alcohol, have been performed. Under these conditions, the incorporation of graphene-like fillers at relatively low concentrations shows an increase in average separation factor for butanol (βBtOH/H2O) from 13.5 for pure PIM-1 membranes to, in some cases, more than double for the MMMs; with the addition of 0.1wt% of reduced amine-functionalized GO βBtOH/H2O reaches 32.9 and 26.9 for the short-chain (OA) and the long-chain (ODA) alkylamines, respectively.

Monodisperse and size-tunable CoO nanocrystals synthesized by thermal decomposition and as an active precursor for Fischer-Tropsch synthesis

CoO nanocrystals with tunable particle sizes were prepared by thermal decomposition of cobalt(II) acetate in different long-chain alkyl amines. These alkyl amines strongly affect the coordination of the amine group to the metal atoms and the metal-amine interaction, thereby mediating the eventual particle sizes in the condensation process. Moreover, CoO nanocrystals were applied for synthesis of supported catalyst, and exhibited higher catalytic activity in Fischer-Tropsch reaction, demonstrating that nanocrystals are active precursor. The TOF of CO on CoAl-n catalyst obtained from CoO nanocrystals is ∼1.5 times higher than that on conventional catalyst with the same particle size.

A Novel Nanodrag Reducer for Low Permeability Reservoir Water Flooding: Long-Chain Alkylamines Modified Graphene Oxide

Chemical modification of graphene oxide (GO) by grafting hydrophobic chains on the surface has drawn much attention nowadays in the academic world, and it was suggested that modified GO could lead to new functionalized materials with specific structure and different properties. In this paper, modified GO (M-GO) were synthesized by chemically grafting alkylamines with varying chain lengths on the graphene oxide surface. Successful grafting of alkylamines was confirmed using Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Raman spectroscopy measurements. In addition, we investigated the properties of M-GO as nanodrag reducer in low permeability reservoir water flooding. Water contact angle (CA) measurements revealed that the hydrophobic nature of GO depended on the chain length of the grafted alkylamines. And flooding experiments showed that the hexadecylamine- and octadecylamine-modified GO had an ability to reduce water injection pressure and improve water-phase permeability of the low permeability reservoirs during water flooding. So the M-GO would have potential applications in oilfield exploitation.