Inspired by the concept of lipophilic and hydrophilic linkers, extended surfactants have been proposed as highly desirable candidates for the formulation of microemulsions with high solubilization capacity and ultralow interfacial tension (IFT), especially for triglyceride oils. The defining characteristic of an extended surfactant is the presence of one or more intermediate‐polarity groups between the hydrophilic head and the hydrophobic tail. Currently only limited information exists on extended surfactants; such knowledge is especially relevant for cleaning and separation applications where the cost of the surfactant and environmental regulations prohibit the use of concentrated surfactant solutions. In this work, we examine surfactant formulations for a wide range of oils using dilute solutions of the extended surfactant classes sodium alkyl polypropyleneoxide sulfate (R‐(PO)x−SO4Na), and sodium alkyl polypropyleneoxide‐polyethyleneoxide sulfate (R‐(PO)y‐(EO)z−SO4Na). The IFT of these systems was measured as a function of electrolyte and surfactant concentration for polar and nonpolar oils. The results show that these extended surfactant systems have low critical micelle concentrations (CMC) and critical microemulsion concentrations (CμC) compared with other surfactants. We also found that the unique structure of these extended surfactants allows them to achieve ultralow IFT with a wide range of oils, including highly hydrophobic oils (e.g., hexadecane), triolein, and vegetable oils, using only ppm levels of these extended surfactants. It was also found that the introduction of additional PO and EO groups in the extended surfactant yielded lower IFT and lower optimum salinity, both of which are desirable in most formulations. Based on the optimum formulation conditions, it was found that the triolein sample used in these experiments behaved as a very polar oil, and all other vegetable oils displayed very hydrophobic behavior. This unexpected triolein behavior is suspected to be due to uncharacterized impurities in the triolein sample, and will be further evaluated in future research.

Two homologous series of double-tail hybrid surfactants containing a hydrocarbon chain and a fluorocarbon chain attached to the same hydrophilic head group have been synthesized. The micellar solutions of such hybrid surfactants have been studied by conductance, surface tension, 19F NMR and 'H NMR. The dependence of the cmc on the chain length follows Klcven's equation. The micellar aggregation numbers are 10-35 and become smaller as the chain length increases. When the hydrocarbon chain bears three carbons or more, both the fluorocarbon and the hydrocarbon chains are incorporated inside the micelle. IntroductionThere has been a continuous effort in industry to prepare new formulations of detergents by changing the compositions of the surfactants, builders, and additives. However, there is relatively little development in the synthesis and characterization of new surfactants that have unusual structures, properties, and applications. The hybrid surfactants described in this paper represent part of our effort in this direction. They are composed of a hydrocarbon (HC) chain and a fluorocarbon (FC) chain attached to the same hydrophilic head group and are a new category of compounds which have not been explored previously.Doubletail surfactants with two HC chains attached to a sulfate head group have been studied by Winsorl and Evans2 in the 1950s. These homologous compounds of sodium dialkyl sulfate have the structural formulae RR'CHOS03Na, in which R and R' are unbranched HC chains with R having a longer chain length than R'. The hybrid surfactants reported here have similar structures, except that one of the chains is an unbranched FC chain.It has long been noticed that fluorinated surfactants are particularly efficient in lowering surface tension. Normally, in the mixture of a FC surfactant with a suitable HC surfactant, the FC surfactant reduces the surface tension while the HC surfactant aids in the reduction of the interfacial tension. The net result can be a system that easily wets and spreads on otherwise hard-tewet ~urfaces.~ However, for ionic surfactants with the same headgroup charge, the application of this advantage of combined effect is limited because of the demixing of HC/FC mixed surfactants. To overcome this problem, some single-chain surfactants containing a FC segment and a HC segment were synthesized, and they show good wettability on solid substrates containing FC ~omponents.~ Recently, Abenin and Cambon reported the synthesis of a series of double-tail HC/FC surfactants R&&NHCH2CHOHCH2NRI "Rm5 Such surfactants are very effective in lowering the surface tension or interfacial ten~ion.~ To our knowledge, hybrid surfactants containing separate FC and HC chains attached to the same head group have not been reported. In the present work, the synthesis, characterization, and the micellar properties of a homologous series of novel double-tail hybrid surfactant are described:

This work examined the use of a single extended surfactant in the microemulsion-based detergency of vegetable oils. The results showed that good canola oil detergency ([80%) was achieved at 25°C using a single extended surfactant (C 14,15 -8PO-SO 4 Na) at concentrations as low as 125 ppm, i.e., significantly lower than the surfactant concentration range of 500-2,500 ppm reported in other microemulsion-based detergency work. It was found that the maximum detergency (95%) was achieved in the type II microemulsion region. These results demonstrate that the microemulsion-based extended surfactant formulation is a promising approach for vegetable oil detergency at low temperature.

No abstract

Multiwalled carbon nanotubes (MWCNTs) were melt‐mixed in a conical twin‐screw extruder with a random copolymer of ethylene and tetrafluoroethylene. Surprisingly, the electrical percolation threshold of the resultant composites was quite low; ∼0.9 wt %. In fact, this value is as low or lower than the value for most MWCNT/semicrystalline polymer composites made with roughly equivalent aspect ratio tubes mixed in a similar manner, for example, melt mixing. This low percolation threshold, suggestive of good dispersion, occurred even though the polymer surface energy is quite low which should make tubes more difficult to disperse. Dynamic mechanical measurements confirmed the rather low percolation threshold. The effect of nanotubes on crystallization kinetics was quite small; suggesting perhaps that a lack of nucleation which in turn reduces/eliminates an insulating crystalline polymer layer around the nanotubes might explain the low percolation threshold. Finally, the modulus increased with the addition of nanotubes and the strain at break decreased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41052.