Nonionic polyoxyethylenes

Nonionic Polyoxyethylenated alkyl-phenols, alkylphenol ethoxylates Emulsifying agents Generally water-soluble Good chemical stability... 

The classical model, as shown in Figure 1, assumes that the micelle adopts a spherical structure [2, 15-17], In aqueous solution the hydrocarbon chains or the hydrophobic part of the surfactants from the core of the micelle, while the ionic or polar groups face toward the exterior of the same, and together with a certain amount of counterions form what is known as the Stern layer. The remainder of the counterions, which are more or less associated with the micelle, make up the Gouy-Chapman layer. For the nonionic polyoxyethylene surfactants the structure is essentially the same except that the external region does not contain counterions but rather rings of hydrated polyoxyethylene chains. A micelle of... 

Interactions of Nonionic Polyoxyethylene Alkyl and Aryl Ethers with Membranes and Other Biological Systems... 

The most common surfactants for analytical applications are nonionic (polyoxyethylene glycol monoethers, polyoxyethylene methyl- -alkyl ethers, t-octylphenoxy polyoxyethylene ethers, and polyoxyethylene sorbitan esters... 

Nonionic Polyoxyethylene (/ ) dodecyl ether (Ci2EO ) or polyethylene glycol ether n = 4 (tetraoxyethylene dodecylether, C 2E04) or tetraethyleneglycol dodecyl ether (TEGDE) or polyoxyethylene(4) lauryl ether (POELE) Polyoxyethylene (n)... 

Silica Nanoparticles. The base-catalyzed hydrolysis of silicon aikoxides in microemulsions produces nanoparticles (20-39). Aqueous ammonia has been used primarily as the base, with AOT and nonionic polyoxyethylene ethers as the main surfactants. Figure 2.2.6 presents a flow diagram for the synthesis of pure silica (23-32) the microemulsion is first prepared and then the alkoxide is added. As can be seen from Table 2.2.1, the microemulsions include the systems AOT/ isooctane/water/ammonia, AOT/toluene/water/ammonia, NP-5/cyclohexane/water/ ammonia, and NP-4/heptane/water/ammonia. Typical reaction times are l -5 days. Various modified silica nanoparticles have also been prepared, including hydropho-... 

Nonionic Polyoxyethylene (pOE or EO) Polyoxyethylene/polyoxypropylene (pOE/pOPor EO/PO) Carbohydrates... 

Hoigne and O Neil (1972) studied several features of the y radiation-initialed polymerization in emulsion. Sodium lauryl sulfate, dioctyl and dibutyl sodium sulfosuccinates, and two nonionic, polyoxyethylene-type emulsifiers were used. Sodium lauryl sulfate gave, by far, the hipest rates and most stable lattices and was used for all of the results reported. The rates were found to be 0.43 order on the dose rate and 0.53 on the... 

Nonionic Polyoxyethylene alcohol All lphenol ethoxylate C H2 .i(OCH2CH2LOH C9Hi9-C6H4-(OCH2CH2) OH... 

Kamegawa and Yoshida (612] studied the pH dependence of the adsorption of several surface-active agents by chemically modified carbons. The uptake of nonionic polyoxyethylene nonylphenyl ether (PO) was not affected by pH, but it deereased with increasing outgassing temperature of the carbon. The uptakes of both the cationic octadecyltrimethylammonium chloride (OT) and the anionic sodium dodecylbenzenesulfonate (DB) exhibited a shallow minimum at intermediate pHs. The authors concluded that the van der Waals force was dominant in the adsorption of PO, while electrostatic attraction and repulsion, respectively, contributed to the behavior of OT and DB. 

Poloxamers are nonionic polyoxyethylene-polyoxypropylene copolymers used primarily in pharmaceutical formulations as emulsifying or solubilizing agents.The polyoxyethylene... 

Nonionic polyoxyethylene ethers Anionic sodium laurylsulfate Cationic quaternary ammonium compounds Bile salts... 

In the case of nonionic polyoxyethylenated surfactants, the CMC value is determined by the number of hydrocarbon groups, n, as well as oxyethylene groups, m, in the mole-... 

PbS hollow nanospheres with diameters of 80-250 nm have been synthesized by a surfactant-assisted sonochemical route from Pb(CH3COO)2, thioacetamide, and sodium dodecylbenzenesulfonate [3]. 200-400 nm hollow silica spheres with mesoporous walls were prepared by the application of ultrasound to a mixture of nonionic polyoxyethylene surfactant and tetraethylorthosilicate. The presence of surface-active agents during ultrasonic synthesis was proved to be effective because surfactants can act as soft templates as well as structure directing agents for the assembly and subsequent... 

In Figure 20.17, we compare a polymer-surfactant mixture, a nonionic polyoxyethylene surfactant and dextran, with a related polymer-polymer mixture, poly(ethylene glycol) and dextran. We can see that the two mixtures phase-separate in qualitatively the same way. 

FIGURE 11.1Z The phase inversion temperatnre (PIT) of an emulsion will depend on the balance of properties of the surfactant and the oil phase. For a series of nonionic polyoxyethylene surfactants and oil phases, the PIT is found to increase with the oil phase carbon number and the POE content of the surfactant. 

If the solubility of a surfactant is highly temperature-dependent, as is the case for many nonionic polyoxyethylene surfactants and long chain fatty acid soaps such as sodium stearate, it will be found that foaming ability will increase in the same direction as its solubility. Nonionic POE surfactants, for example, exhibit a decrease in foam production as the temperature is increased and the cloud point is approached (solubility decreases). Long-chain carboxylate salts, on the other hand, which may have limited solubility and poor foaming properties in water at room temperature, will be more soluble and will foam more as the temperature increases. 

A variety of cationic surfactants are derived from pyridine and imidazole, such as the alkylpyridinium salts and the alkyl imidazolidinium salts. These salts are very stable in aqueous solutions, but absorb UV light which makes them difficult to be used in MLC. Also, surfactants associating a nonionic polyoxyethylene chain with a cationic terminal group have been designed [5],... 

M.F. Borgerding and W.L. Hinze, Characterization and Evaluation of the Use of Nonionic Polyoxyethylene(23)dodecanol Micellar Mobile Phases in RPLC, Anal. Chem., 57 2183 (1985). 

As shown in Figure 18.5, l//,l//-perfluoroalkanols are an important group of intermediates that can be obtained from PFCA fluorides obtained by electrochemical fluorination (or, alternatively, by a telomerization process ). These alcohols are readily converted into polydisperse nonionic polyoxyethylene surfactants by reaction with oxirane (or analogues) in the presence of a catalyst (Scheme 18.13). Borontrifluoride etherate is the classical catalyst for this oxyethylation reaction, but there are claims for the utilization of other catalysts such as aluminum alkoxides, sodium hydroxide, and acidic catalysts. ... 

Based on this same general idea, colloidal dispersions of nanocomposite particles made from silica cores and polymeric overlayers have been successfully prepared using appropriate cationic radical initiators, as described in a recent Japanese patent [100]. Recently, Luna-Xavier et al. also demonstrated the successful formation of nanosize siHca/PMMA composite colloids using AIB A as cationic initiator and a nonionic polyoxyethylenic surfactant (NP30) [63,91,101]. Composite particles made from silica beads surrounded by small heterocoagulated PMMA latexes or a thin polymer layer were produced, depending on the size of the silica beads (Fig. 4.11). 

In situ ellipsometry has been used to investigate the adsorption of zwitterionic dodecyl-A, A-dimethyl-ammonium alkanoates with polymethylene intercharge arms of different lengths on silica, with common aspects being observed in the adsorption features of zwitterionic surfactants with nonionic polyoxyethylenated surfactants. ... 

Zech et al. [90] reported high-temperatiue-stable microemttlsions composed of the room-temperature IL EAN as polar phase. Byrne et al. [91] reported on the solubility of HEWL in aqueous EAN as a function of water content. The structure of micelles formed by nonionic polyoxyethylene alkyl ether nonionic surfactants in the room-temperatrrre IL EAN by small-angle neutron scattering as a function of alkyl and ethoxy chain length, concentration, and temperatrrre, was reported by Araos et al. [92]. 

TRYCOL Ethoxylated Alcohols are nonionic polyoxyethylene surfactants prepared conunercially by the condensation or addition of ethylene oxide to a hydrophobic compound at the site of an active hydrogen. In this case the active hydrogen is at the hydroxyl group on a hydrophobic alcohol. 

Trimethyl dodecylammonium chloride Cetyl trimethylammonium bromide Nonionic Polyoxyethylene alcohol... 

Fitter, P., Colorimetric method for nonionic polyoxyethylene-type surfactants, Chem. Ind., Oct. 20, 1962, 1832-1833. 

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