Amine Oxide Groups Research Articles

A simply prepared amine oxide molecule as a low work function cathode modifier in organic photovoltaics for harvesting ambient light

Organic photovoltaics (OPV) that possibly convert ambient lights to electric energy are under the spotlight as a power supplier for portable, wearable, and Internet of Things devices. In order to enable the commercialization of ambient light harvesters, it is imperative to design and synthesize device components that offer cost-effectiveness, uniform deposition, and efficient charge extraction/collection. Here, we introduce a simple cathode interlayer (CIL) named EtNO for OPV-based ambient light harvesters. EtNO is designed with a chemical structure that does not require complicated conjugated units and is synthesized through a one-step procedure. EtNO CIL shows efficient reductions in the work function of electrodes, attributed to an interfacial dipole induced from an interaction between amine oxide group of EtNO and electrodes. Furthermore, EtNO forms a uniform layer through solution-processing without deteriorative effects on the surface of photoactive layer in OPVs. Therefore, the OPV with EtNO CIL exhibits an improved performance with an output power density of 79.2 μW cm–2 under light emitting diode illumination (1000 lx, 254 μW cm–2) compared to the device with conventional PDINO CIL (73.1 μW cm–2). Studies conducted on OPVs under halogen light illumination and on large-area devices further demonstrate the significant potential of EtNO as a CIL.

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.

Incorporating tertiary amine and thioether in polyarylene sulfide sulfone membranes for multiple separations

Polymers have been widely applied for membrane separations; however, most polymer membranes lack adjustable pores and cannot serve in multiple separations once fabricated. Here, a novel block copolymer, polyarylene sulfide sulfone/amide tertiary amine (PASS/ATA), containing tertiary amine and thioether groups was designed for membrane fabrication as it can be self-assembled into a well-defined, uniform, and continuous pores. Via a facile oxidization procedure, the tertiary amine and thioether groups in the membrane molecular chains were converted into amine oxide and sulfone groups, respectively, which dramatically narrows down the pores of the membranes and greatly improves dye rejection, altering the application of the membranes from ultrafiltration (UF) to nanofiltration (NF). Furthermore, after the thioether units were oxidized into sulfone groups, the solvent resistance of the membranes was greatly increased, ensuring the application of the oxidized membranes in organic solvent nanofiltration (OSN). Dissipative particle dynamics (DPD) simulation was applied to shed insight on the formation mechanisms and transformation processes, as well as to explain the decrease of pore size combined with the enhancement of solvent resistance. As a result, combing tertiary amines with thioether groups in polymer chains endows the membrane with multiple functionalities, allowing for multiple separations including UF, NF, and OSN.

Maleic and Methacrylic Homopolymers with Pendant Dibutylamine or Dibutylamine Oxide Groups as Kinetic Hydrate Inhibitors.

Kinetic hydrate inhibitors (KHIs) are applied in oil and gas fields to prevent gas hydrate formation, most often in cold subsea flow lines. The main component in industrial KHI formulations is a water-soluble polymer with many amphiphilic groups of which the hydrophilic part is most commonly the amide functional group. In the last decade, we have investigated polyamine oxides as alternatives to polyamides due to the strong hydrogen bonding of the amine oxide group. Here, we report the KHI performance of maleic and methacrylic homopolymers with dialkylamine and dialkylamine oxide pendant groups. Performance screening experiments were conducted under high pressure with a Structure II-forming natural gas mixture in steel rocking cells using the slow (1 °C/h) constant cooling test method. Polymers with dibutylamine groups gave much better KHI performance than polymers with dimethylamine or diethylamine groups. Polyamines formed from polymaleic anhydride reacted with 3-(dibutylamino)-1-propylamine (DBAPA) or 2-(dibutylamino)-ethanol (DBAE) gave good water solubility and good KHI performance, probably due to self-ionization between the dibutylamino and carboxylic acid groups. The lack of self-ionization for the methacryl homopolymers of DBAPA and DBAE explains why these polymers are not water-soluble. Oxidation of the maleic or methacryl polyamines to polyamine oxides gave water-soluble polymers with good compatibility with brines (0.5-7.0 wt % NaCl), but only the DBAPA-based polyamine oxides gave improved KHI performance compared to the polyamines. Poly(3-(dibutylamino oxide)-1-propyl methacrylamide) gave a similar performance to commercial N-vinyl pyrrolidone:N-vinyl caprolactam 1:1 copolymer and without a cloud point in deionized water up to +95 °C.

Non-Amide Polymers as Kinetic Hydrate Inhibitors-Maleic Acid/Alkyl Acrylate Copolymers and the Effect of pH on Performance.

Kinetic hydrate inhibitors (KHIs) have been used for over 25 years to prevent gas hydrate formation in oil and gas production flow lines. The main component in KHI formulations is a water-soluble polymer with many amphiphilic groups, usually made up of amide groups and adjacent hydrophobic groups with 3–6 carbon atoms. KHI polymers are one of the most expensive oilfield production chemicals. Therefore, methods to make cheaper but effective KHIs could improve the range of applications. Continuing earlier work from our group with maleic-based polymers, here, we explore maleic acid/alkyl acrylate copolymers as potential low-cost KHIs. Performance experiments were conducted under high pressure with a structure II-forming natural gas mixture in steel rocking cells using the slow (1 °C/h) constant cooling test method. Under typical pipeline conditions of pH (4–6), the performance of the maleic acid/alkyl acrylate copolymers (alkyl = iso-propyl, iso-butyl, n-butyl, tetrahydrofurfuryl, and cyclohexyl) was poor. However, good performance was observed at very high pH (13–14) due to the thermodynamic effect from added salts in the aqueous phase and the removal of CO2 from the gas phase. A methyl maleamide/n-butyl acrylate copolymer gave very poor performance, giving evidence that direct bonding of the hydrophilic amide and C4 hydrophobic groups is needed for good KHI performance. Reaction of the maleic anhydride (MA) units in MA/alkyl acrylate 1:1 copolymers with dibutylaminopropylamine or dibutylaminoethanol gave polymers with good KHI performance, with MA/tetrahydrofurfuryl methacrylate being the best. Oxidation of the pendant dibutylamino groups to amine oxide groups improved the performance further, better than poly(N-vinyl caprolactam).

Complexation of tannic acid with polyoxypropylene diamine in water and application for the preparation of hierarchically structured functional surfaces

We rationalize that a water-soluble low molecular weight polyoxypropylene diamine (i.e., Jeffamine® D400 polyetheramine), capable of various types of noncovalent molecular interactions through its amine and propylene oxide groups, presents a simple yet versatile opportunity to form complexes with natural polyphenol of tannic acid (TA) and be exploited to engineer functional materials and surfaces. By investigating TA-D400 complexation behaviors in water, we demonstrate that mixing weakly acidic TA and neutral D400 solutions of stock concentrations above 1.0 mg/mL allowed easy formation of colloidally stable TA-D400 complexes. Such complexes were characterized as cationic nanoparticles of typical hydrodynamic diameters less than 300 nm. Mixing ratios were found to be less of an influencer on complexation. The TA-D400 intermolecular complexation was shown to be driven primarily by hydrophobic interaction in conjunction with ionic association. A simple immersion process can induce the formation of substrate-independent, hierarchically structured, and highly hydrophilic surfaces because of adsorption of TA-D400 complexes. Such functional surfaces not only can potentially modulate cell-material interactions shown by our brief in vitro fibroblast cell culture study, but also are feasible for in situ facile reduction of HAuCl4 to achieve integration of gold nanoparticles for function enrichment. This TA-D400 system adds a new option to the toolbox of polyphenol-mediated green technologies for surface engineering.

Stability of Nitrogen-Containing Polyfluoroalkyl Substances in Aerobic Soils.

Zwitterionic per- and polyfluoroalkyl substances (PFASs) used in aqueous film-forming foams (AFFFs) could face diverse environmental fates once released at military bases, airports, fire-training areas, and accidental release sites. Here, we studied for the first time the transformation potential of four electrochemical fluorination (ECF)-based PFAS zwitterions (two carboxyl betaines and two tertiary amines) in aerobic soils. The two perfluoroalkyl sulfonamide derivatives were precursors to perfluorooctanesulfonate (PFOS), while the amide derivatives were precursors to perfluorooctane carboxylate (PFOA). These zwitterions and four other previously reported zwitterions or cations were compared for their transformation pathways and kinetics. Structural differences, especially the nitrogen head groups, largely influenced the persistence of these compounds in aerobic soils. The perfluoroalkyl sulfonamide-based compounds showed higher microbial stability than the corresponding perfluoroalkyl amide-based ones. Their stability in aerobic soils is ranked based on the magnitude of DT50 (time for 50% of substance to disappear): quaternary ammonium ≈ carboxyl betaine ≫ tertiary amine > amine oxide. The PFASs containing quaternary ammonium or betaine groups showed high stability in soils, with the longest DT50 likely to be years or decades, while those with tertiary amine or amine oxide groups showed DT50 of weeks or months. These eight ECF-based precursors provide insights into the degradation pathways and persistence in surface soils of other perfluoroalkyl cations and zwitterions present in AFFFs.

Non-amide based zwitterionic poly(sulfobetaine methacrylate)s as kinetic hydrate inhibitors

Applying kinetic hydrate inhibitors (KHIs) to avoid the pipeline blockage caused by hydrate formation in gas and oil industry is a comparatively effective and cost-saving method. The main ingredients in most KHIs are water-soluble polymers containing repeating amide group units, placed structurally close to hydrophobic groups. In this report we have synthesized a class of non-amide polymers, zwitterionic poly(sulfobetaine methacrylate)s, and investigated them as KHIs for the first time. Results show that the best zwitterionic polymers have good KHI efficacy with the key performance parameter being the length of the alkyl chain on the monomer unit side chains. Copolymer of the zwitterionic monomers and N-isopropylmethacrylamide (NIPMAM) gave much better increase in KHI performance with increasing concentration than the zwitterionic homopolymers. This result together with other related studies suggests that strong hydrogen-bonding groups like amide or amine oxide groups are important for high KHI performance. Reasons for this are discussed.

Effects of the spacer length on the aggregate formation and the gelation of alkylamide amine oxides

Three kinds of alkylamide amine oxides having one, two, and three amides were synthesized, and their solution properties such as the surface tension and the viscosity were examined. The effects of the spacer group length n between amide and dimethyamine oxide group as well as the number of amide groups were examined with respect to the aggregation behavior. For short spacer lengths, amide groups join the hydrophilic head group, while for long spacer lengths, amide groups and a part of the spacer groups are suggested to reside in the micelle palisade layer. In a series of amphiphile having three amide groups, gels formed at a high concentration of 50 mM were tentatively grouped into two types: A and B, depending on the spacer length n. For Gel-A, the gelling temperature T gel increased linearly with n but it was scarcely affected by the protonation of amine oxide (AO) group. For Gel-A, fiber-like aggregates were observed in cryo-TEM images. For Gel-B, values of T gel were higher by 18 ± 2 K than those of Gel-A for a given n. Cryo-TEM images of Gel-B showed wide ribbon-like aggregates. On ionization of AO group, Gel-B transformed into Gel-A.

Selective recovery of palladium using an innovative functional polymer containing phosphine oxide

A new polymeric sorbent powder (MP-102) containing phosphine oxide groups was developed for the selective recovery of palladium by sorption from acidic effluents containing base metals such as nickel and copper. Experiments show an interesting affinity of MP-102 to palladium species with sorption capacity up to 1mmolg−1 at pH 2, fast kinetics and up to 96% selectivity for Pd in presence of Cu and Ni at pH 1. It was found that 99% of the sorbed palladium can be stripped by elution with an acidified solution of thiourea. The influence of various operating parameters (pH, chloride concentrations and temperature) on Pd sorption equilibria was studied in presence of copper and nickel in order to investigate their influence on the sorption selectivity of the palladium species and to investigate the metal binding mechanisms. Experiments, supported by DFT calculations, suggest a coordination of Pd and Ni by the phosphine oxide groups, preferably in a bidentate mode (chelation), whereas Cu appears to bind to both amine and phosphine oxide groups. The sorption selectivity for palladium is likely due to the energy gain upon palladium coordination to MP-102 which is at least 40kJmol−1 higher than upon copper and nickel coordination.

Preparation and Properties of Thermo-Sensitive Resin for Processless CTP Plate

Computer-to-Plate (CTP) technology has been becoming an important topic of research and application during the era of digital printing. Processless CTP plate is regarded as a leading candidate for CTP plate due to its many merits such as friendly to environment, saving resources, good quality of imaging, low cost and so on. A new thermo-sensitive resin which could be used in processless CTP plate was synthesized by solution polymerization with styrene and N, N-dimethylaminoethyl methacrylate in 1:1 molar ratio using azodiisobutyronitrile (AIBN) as initiator and 1,4-dioxane as solvent and then by hydrogen peroxide (H2O2) oxidation of the tertiary amine groups of the copolymer. It could be found from thermogravimetric analysis that there was a slight weight loss before 120°C owing to water evaporation; and there was an obvious weight loss from 140°C to 230°C owing to the decomposition of amine oxide group; and there was a large weight loss after 300°C owing to the decomposition of thermo-sensitive resin. It was found from contact angle analysis that the contact angle of the thermo-sensitive resin film reached maximum 75° after baking for 7 min at 140°C, which means that the decomposition rate of amine oxide group is slow and parts of amine oxide groups decompose incompletely. The contact angle of the thermo-sensitive resin film reached maximum 80° after baking for 5 min at 160°C or 2 min at 180°C which means that thermal decomposition rate increases with the increase of temperature and the decomposition occurs completely. It was also found that the resin film could be easily washed away from the substrate with neutral water before heat-treatment, but it could no longer be removed after the heat-treatment of baking for 5 min at 140°C or baking for 2 min at 160°C or baking for 1 min at 180°C. This new thermo-sensitive resin could be used in chemical-free thermal laser imaging application.

Protonation Behavior and Solution Properties of Amine Oxide Surfactants Containing a Pyridyl Group

Hydrogen bonding between surfactant molecules plays an important role in self-assembly formation. For long alkyl chain amine oxide surfactants, the specific protonation degree dependence of some solution properties has been considered to be due to hydrogen bonding between protonated and deprotonated species. In addition to this type of hydrogen bonding, we introduced a pyridyl group into an alkylamine oxide molecule as a new hydrogen-bonding site. The pyridyl group has three different structural isomers based on the position of the substituent. An amine oxide group in pyridylamine oxides was preferentially protonated. In addition, protonation of the pyridyl group revealed a pronounced substituent position effect on the critical micelle concentration, micellar size, and solubilization of oil-soluble dye into micelles. The intermolecular or intramolecular hydrogen bond formation could be controlled by altering the substituent position.

Solution Behavior of Long–alkyl–chain Amide Amine Oxide Surfactants Having Multiple Hydrogen-bonding Sites

Abstract We investigated the surface tension behavior and gelation ability of amide amine oxide surfactants with different numbers and arrangements of amide groups, and different spacer lengths between the amide and amine oxide groups. Whether the amide groups work as the polar head groups or they are incorporated in the hydrophobic part depended on the spacer length. The number and arrangement of amide groups were important in the hydrogen-bond formation between surfactant molecules.

Conformational Preferences of 3-(Dimethylazinoyl)propanoic Acid as a Function of pH and Solvent; Intermolecular versus Intramolecular Hydrogen Bonding

The conformational equilibrium of 3-(dimethylazinoyl)propanoic acid (DMAPA, azinoyl = N(+)(O(-)) has a weak pH-dependence in D(2)O, with a slight preference for trans in alkaline solutions. The acid ionization constants of the protonated amine oxide and carboxylic functional groups as determined by NMR spectroscopy were 7.9 x 10(-4) and 6.3 x 10(-6), respectively. The corresponding value of K(1)/K(2) of 1.3 x 10(2) is not deemed large enough to provide experimental NMR evidence for a significant degree of intramolecular hydrogen bonding in D(2)O. Conformational preferences of DMAPA are mostly close to statistical (gauche/trans = 2/1) in other protic solvents, e.g., alcohols. However, the un-ionized form of DMAPA appears to be strongly intramolecularly hydrogen-bonded and gauche in aprotic solvents.

The coordination chemistry of divalent cobalt, nickel and copper. Part 12. A comparison of the nature of the cobalt and nickle complexes isolated when using P-( N,N-dimethylaminomethyl)- P,P-diphenylphosphine oxide and P-( N,N-dimethylaminoethyl)- P,P-diphenylphosphine oxide as ligands

The ligands P-( N,N-dimethylaminomethyl)- P,P-diphenylphosphine oxide (dmpo) and P-( N,N-dimethylaminoethyl)- P,P-diphenylphosphine oxide (depo) were reacted with selected divalent cobalt and nickel salts. The resultant complexes were analysed and characterised. In all cases dmpo behaved as a bidentate ligand by coordinating through the amine and phosphine oxide groups while depo usually reacted in a monodentate manner. The complexes (MX 2) 3(dmpo) 4, where M = Co, Ni and X = Cl, Br, were shown to consist of two pentacoordinate M(dmpo) 2X + cations and one tetrahedral MX 4 2− anion. Reaction of equimolar quantities of CoCl 2 and depo resulted in the isolation of CoCl 3(H·depo). This complex was found to have a tetrahedral coordination sphere consisting of three chloride atoms and one phosphine oxide. It was suspected that a tautomerism type reaction produced the proton in H·depo +. The corresponding NiCl 3(H·depo)complex could only be obtained by the addition of hydrochloric acid. The reaction of equimolar amounts of CoCl 2, dmpo, and HCl yielded (H·dmpo) 2[CoCl 4]. The complex Co(dmpo) 2(SCN) 2 which contained two N-bonded thiocyanate groups was assigned a distorted octahedral coordination sphere. However, in Co(depo) 2(SCN) 2 the phosphine oxide groups did not bond and the coordination sphere had a distorted tetrahedral symmetry. The insoluble nature of Ni(depo) 2(ClO 4) 2·2H 2O resulted in inconclusive characterisation data. The complexes [M(dmpo) 2(mecn) 2](ClO 4) 2, mecn = methyl cyanide, were assigned an octahedral coordination sphere. Removal of methyl cyanide from this sphere resulted in complexes in which there was evidence for interaction between the perchlorate groups and the metal ions.

Plasma-polymerized thin films containing anion and cation groups

Thin films containing anion and cation groups were prepared by hydrolysis and quaternization of polymers plasma-polymerized from bis(dimethylamino)methlvinylsilane (BDMAMVS). The products were investigated by electron spectroscopy for chemical analysis and infrared spectroscopy. Amide groups in the plasma polymers from BDMAMVS were hydrolyzed to carboxyl groups with an octylbromide / water mixture (1 : 6 mole ratio) at 80°C for 16 h. Amine and amineoxide groups in the plasma polymers were quaternized by exposure to methylbromide vapor at 50°C for 48 h to give quaternary ammonium groups. The combination of hydrolysis and quaternization yielded thin films containing both anion and cation groups.

Formation of rodlike micelles of dimethyloleylamine oxide in aqueous solutions: effects of addition of HCl and NaCl on the micelle size and the intermicellar interaction

Angular dependence of light scattering has been measured for aqueous solutions of dimethyloleylamine oxide in the presence of HCl and NaCl. In micellar solutions more concentrated than 0.1×10−2 g cm−3, rodlike micelles are dominantly formed, and their properties are strongly reflected in the characteristics of the solutions. The aggregation number, radius of gyration and even flexibility of the rodlike micelles increase with the addition of HCl as well as NaCl. The increase of HCl concentration up to 10−3 N makes the aggregation number of rodlike micelles as large as 58,000, when 0.01 M NaCl is present. The large micelle size would be stabilized by the dehydration of the amine oxide group and the hydrogen bonding between nonprotonated and protonated molecules in a micelle.

Moisture sensor devices composed of thin films plasma-polymerized from amino-groups-containing silanes

Quaternization of thin films plasma-polymerized from trimethylsilyldimethylamine, bis(dimethylamino)methylsilane, bis(dimethylamino)methylvinylsilane with methylbromide was investigated by elemental analysis, infrared spectroscopy, and ESCA. The modification of amino and amineoxide groups in these plasma polymers was accomplished to yield quaternary nitrogen residues of N + (CH 3)HBr −, N + (CH 3) 2Br −, and N + (OCH 3)Br − groups. These quaternized plasma-films are sensitive to moisture, and their electrical resistance decreases exponentially with increasing the relative humidity from 20 to 90% by four orders. The hysteresis in the electrical resistance in cyclically changing the relative humidity is not so large, the response time being within 20 s.

Preparation of amino group‐containing polymers by plasma polymerization

AbstractPlasma polymerizations of bis(dimethylamino)methylsilane (BDMAMVS), bis(dimethylamino) methylvinylsilane (BDMAMVS), and trimethylsilyldimethylamine (TMSDMA) were investigated by elemental analysis, IR spectroscopy, and ESCA. Polymer deposition was fairly faster in the BDMAMVS and TMSDMA systems than in the BDMAMS system, indicating that vinyl and methyl substituents contribute to polymer formation, whereas hydrogen substituents disturb the polymer formation. IR and ESCA spectra for these polymers showed that some dependence of the polymers formed in the chemical composition on the nature of the monomers. A part of methylamino groups in these monomers were oxidized to give amido and amine oxide groups. BDMAMVS and TMSDMA yielded polymers with few fragmentations of methylamino groups, whereas the polymers formed from BDMAMS had no methylamino groups.

Cope elimination and complexation of poly(dimethylaminoethyl methacrylate N‐oxide)

AbstractPoly(dimethylaminoethyl methacrylate N‐oxide) (poly(DMAEMNO)) was prepared by oxidation of poly(dimethylaminoethyl methacrylate) with hydrogen peroxide in methanol. From thermogravimetric and IR spectroscopic investigations Cope elimination of amine oxide group in poly(DMAENO) was found to occur at 120–150°C. The postpolymerization of partially pyrolyzed polymer carrying vinyl ester group as pendant was performed with azobisisobutyronitrile at 60°C in methanol to give cross‐linked polymer that was found to form hydrogel. Poly(DMAEMNO) gave metal–polymer complexes with CuCl2, ZnCl2, and CoCl2. Cobalt–polymer complex had a constitution of 1:2 of metal ion to amine oxide group, while copper– and zinc–polymer complexes seemed to have structures of 1:1 and 1:2 of metal ion to amine oxide group. Furthermore, polymer complexes of poly(DMAEMNO) with poly(methacrylic acid) and poly(acrylic acid) were found to be formed by mixing aqueous solutions of both polymers and also by radical polymerization of the acid monomers in the presence of poly(DMAEMNO). From elemental analysis, thermogravimetric investigation, and measurement of turbidity it was concluded that the resulting polymer–polymer complexes contained more than one acid monomer unit per one N‐oxide unit.