Surfactants mixed nonionic

The absorption of drugs from the rectal [32] cavity has been studied in some detail. Muranishi et al. [34] have shown that a significant increase in the absorption and lymphatic uptake of soluble and colloidal macromolecules can be achieved by pretreating the rectal mucosal membrane with lipid-nonionic surfactant mixed micelles. They found no evidence of serious damage of the mucosal membrane. Davis [30] suggested that the vaginal cavity could be an effective delivery site for certain pharmaceuticals, such as calcitonin, used for the treatment of postmenopausal osteoporosis. 

Below the CMC, the surfactant mixing in monolayers composed of similarly structured surfactants approximately obeys ideal solution theory. This means that the total surfactant concentration required to attain a specified surface tension for a mixture is intermediate between those concentrations for the pure surfactants involved. For mixtures of ionic/nonionic or anionic/cationic surfactants, below the CMC, the surfactant mixing in the monolayer exhibits negative deviation from ideality (i.e., the surfactant concentration required to attain a specified surface tension is less than that predicted from ideal solution theory). The same guidelines already discussed to select surfactant mixtures which have low monomer concentrations when micelles are present would also apply to the selection of surfactants which would reduce surface tension below the CMC. 

In order to define a ionic/nonionic surfactant solution with high salinity/hardness tolerance, the following criterion should be followed. The mixed micelle should have as large of a negative deviation from ideality as possible. Surfactant mixture characteristics which result in this have already been discussed. The nonionic surfactant should have a high cloud point. Otherwise the amount of nonionic surfactant which can be added to the system is limited to low levels before phase separation occurs. If possible, a mixed ionic surfactant should be used for reasons Just discussed. There is no such benefit to using mixed nonionic surfactants, although this is not necessarily detrimental either. 

The variation of the mixture critical micelle concentration (CMCf ) with temperature and with overall surfactant composition has been studied using ultrafiltration for two binary mixed nonionic/anionic systems. 

Many models have appeared in the literature describing interactions of surfactants in mixed micelles (1-14). For nonionic surfactants mixing nonideally, the key references up to 1984 have been recently summarized (15). Comparatively few models have been developed for ionic surfactants (5,6,10-12) and fewer models which acknowledge ionic/nonionic interactions are available (5-7). Since many practical surfactant mixtures involve ionic and nonionic surfactants which interact with each other and with added salts, it is important to develop explicit ionic/nonionic models. 

Add with mixing Nonionic Surfactant-HLB 13 Add with mixing... 

Al-Saden, A. A., A. T. Florence, T. K. Whatley, F. Puisieux, and C. Vautuion. 1982. Characterization of mixed nonionic surfactant micelles by photon correlation spectroscopy and viscb Hiylloid Interface Sci 86 51-56. 

Field Application. The micellar-polymer process for enhanced oil recovery has been used in many field trials. Petroleum sulfonates are the most commonly used surfactant 41, 42). Other surfactants have been used, such as ethoxylated alcohol sulfates 43) and nonionic surfactants mixed with petroleum sulfonates 44). 

Mixed solutions of cationic surfactants and nonionic poly(ethylene glycol) or block copolymers were employed for the synthesis of monolithic trimodal porous silica.[176] Lyotropic mixtures of block copolymers of different lengths with hydrophilic linear PEO chains were also applied to their nanocasting into bimodal micro-mesoporous silica to formulate the dependence of the mesopore sizes and the microporosity on the lengths or sizes of the hydrophobic and the hydrophilic blocks, but the mesostructures were worm-type in morphology and several hundred nanometers or more in size. 

This section briefly describes the anionic and nonionic surfactants commonly used in commercial HDLD formulations. Cationic surfactants, although used on a large scale, are found predominantly in rinse-added fabric softener products. LAS, alcohol ethoxylates, and alkyl ether sulfates are three of the most widely used surfactants in liquid laundry detergents [44], Recently, various external considerations, such as environmental pressures, have prompted manufacturers to change their surfactant mix to include newer natural-based surfactants [45-47], including alkyl polyglucosides (Henkel) [48],... 

Kunieda H, Yamagata M. Three phase behavior in a mixed nonionic surfactant system. Colloid Polym Sci 1993 271 997-1004. 

The situation is very different for the more rigid polyelectrolyte xanthan. The foam films made with DTAB solutions are very unstable. When using DTAB or CTAB which alone give stable foam films, the incorporation of the polymers in the solutions also leads to unstable films. This behaviour is particular to the cationic surfactants indeed stable foam films can be made with nonionic surfactants and all the polymers. The data of Figure 8 for xanthan were obtained in this way.29 We have seen that in the case of cationic surfactants, mixed poly-... 

Unlike the SDS/PEI system the cmc value does not decrease markedly in the solutions of nonionic surfactant C12E10 and Triton-X-l(X) when the polymer is added. This is in line with the assumption on the weak affinity between the nonionic snrfactant and polymers. However, as will be shown below a rather high probability occnrs that the mixed nonionic... 

The majority of miniemulsions reported in the literature have been stabilized with anionic surfactants such as sodium dodecyl sulfate (SDS), probably because of the widespread use of anionic surfactants in conventional emulsion polymerization, and due to their compatibility with neutral or anionic monomers and anionic initiators. Other types of surfactant have also been used, such as cationic, nonionic, and mixed nonionic/anionic, reactive as well as nonreactive surfactants. The surfactants useful for miniemulsion polymerization should meet the same requirements as in the conventional emulsion polymerization. 

It is worth remarking that this is not the case for ethoxylated nonionic surfactants [75] or for some anionic ones such as disulfonates [76]. Sometimes surfactant mixing allows the cosurfactant requirements to be minimized [77]. 

Acrylamide was successfully polymerized in a supercritical inverse emulsion composed of an ethane-propane mixture as the continuous phase, water and acrylamide as the dispersed phase, and a mixed nonionic surfactant system as the emulsifier [86], AIBN [2,2 -azobis(isobutyronitrile)] was the initiator. The polymerization was subsequently repeated in supercritical CO2 [87]. The C02-philic surfactant used to produce the inverse emulsion was an amide, end-capped poly(hexafluoropropylene oxide). The process yielded polymers of average molecular weights from 5 x 10 to 7 x 10. ... 

In this chapter, a brief theoretical background on the rheological behavior of viscoelashc worm-like micelles is given. It is followed by a discussion on the temperature-induced viscosity growth in a water-surfactant binary system of a nonionic fluorinated surfactant at various concentrations. Finally, some recent results on the formation of viscoelastic worm-like micelles in mixed nonionic fluorinated surfactants in an aqueous system are presented. 

Viscoelastic Worm-Like Micelles in Mixed Nonionic Fluorinated Surfactant Systems... 

As already stated, several studies have been pubUshed using nonionic surfactant systems. The formation of viscoelastic micellar solutions in mixed nonionic systems is interesting in basic research-as the relation between packing constraints of hydrophobic chains and micellar growth would be clarified since the complicated interaction between the counterion and headgroup does not occur-as well as in applications such as cosmetics or pharmacy, where the avoidance of ionic additives is often desirable. 

A remarkable contribution in recent years was to have shown for the first time the formation of highly viscoelastic worm-like micelles (Figure 12) in mixed nonionic surfactant systems [110]. This finding allowed to clarify the relation between packing constraints of hydrophobic chains and micellar growth because the complex interactions between counterions (present in ionic surfactant systems) and headgroups had not to be taken into consideration. 

Acharya, D.P., and Kunieda, H. (2003) Formation of viscoelastic wormlike micellar solutions in mixed nonionic surfactant systems. J. Phys. Chem. B, 107, 10168-10175. 

A., Hattori, K., and Kunieda, H. (2004) Effect of nonionic head group size on the formation of worm-like micelles in mixed nonionic/cationic surfactant aqueous systems. J. Chem. Eng. Soc. Jpn., 37, 622-529. 

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