Interactions polymer-surfactant

Surfactants constitute some of the most important (in terms of function, not quantity) ingredients in cosmetic and toiletry products, foods, coatings, pharmaceuticals, and many other systems of wide economic and technological importance. In many, if not most, of those applications, polymeric materials, either natural or synthetic, are present in the final product formulations or are present in the targets for their use. Other surfactant applications, especially in the medical and biological fields, also potentially involve the interaction of polymers (including proteins, nucleosides, etc.) with surfactant system. 

Interactions between surfactants and natural and synthetic polymers have been studied for many years with varying degrees of understanding and experimental control. Although the basic mechanisms of surfactant-polymer interaction are reasonably well known, there still exists substantial disagreement as to the details of some of the interactions at the molecular level. Observations 

FIGURE 14.4. For strongly adsorbed polymers at low surface coverage (e.g., 0.5), each chain will nsnally have many points of contact (a). As the fraction of coverage increases, chains may begin to reaccommodate to allow more chains to adsorb with longer tails and loops. The result may be a thicker (and therefore more effective) adsorbed layer (b). 

The forces controlling surfactant interactions with polymers are identical to those involved in other solution or interfacial properties, namely, van der Waals or dispersion forces, the hydrophobic effect, dipolar and acid-base interactions, and electrostatic interactions. The relative importance of each type of interaction will vary with the natures of the polymer and surfactant so that the exact characters of the complexes formed may be almost as varied as the types of material available for study. 

Experimental methods for investigating polymer-surfactant interactions vary widely, but they generally fall into two categories those that measure the macroscopic properties of a system (viscosity, conductivity, dye solubilization, etc.) and those that detect changes in the molecular environment of the inter- 

Studies on the interaction between surfactants and styrene-ethylene oxide block co-polymers, however, indicate that the polymers exhibit, in the presence of surfactant, typical polyelectrolyte character. This, it has been suggested [264], is due to interaction repulsions between like charges of the NaDS ions adsorbed onto the polyoxyethylene blocks. Investigating the interaction of the same detergent with methylcellulose and poly(vinyl alcohol), Lewis and Robinson [265] also observed the polyelectrolyte character of the polymer-surfactant complexes. A complex between non-ionic surfactants and a polycarboxylic acid in water can solubilize oil-soluble dyes below the surfactant CMC [268]. The complex containing the solubilizate can be precipitated the solubilizate remains in the precipitated complex and is leached out only slowly on placing the precipitate in fresh solvent. This has potential pharmaceutical implications. Halothane uptake by coacervate systems of gelatin-benzalkonium [269] has 

Both ionic and non-ionic surfactants influence the rheological behaviour of gum arabic solutions [253]. Brij 96 increases the relative viscosity of gum arabic up to a 5 % surfactant concentration at concentrations of gum up to 10 %. NaLS also increases the viscosity of the gum but beyond 1 % NaLS the viscosity is reduced (Fig. 6.38). 

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Originating from Cornwall, Peter Griffiths studied initially at University College, North Wales (1985-88), and subsequently the University of Bristol (PhD, 1991). After post-doctoral positions in Bristol and Stockholm, he moved to a lectureship at Cardiff in 1995. Aged 32, his research interests centre around colloidal systems, in particular polymer/surfactant interactions. 

T. R. French and C. B. Josephson. The effect of polymer-surfactant interaction on the rheological properties of surfactant-enhanced alkaline flooding formulations Topical report. US DOE Fossil Energy Rep NIPER-635, NIPER, February 1993. 

Fluorescence spectroscopy is also particularly well-suited to clarify many aspects of polymer/surfactant interactions on a molecular scale. The technique provides information on the mean aggregation numbers of the complexes formed and measures of the polarity and internal fluidity of these structures. Such interactions may be monitored by fluorescence not only with extrinsic probes or labelled polymers, but also by using fluorescent surfactants. Schild and Tirrell [154] have reported the use of sodium 2-(V-dodecylamino) naphthalene-6-sulfonate (SDN6S) to study the interactions between ionic surfactants and poly(V-isopropylacrylamide). 

Polymer/Surfactant Interactions. Interaction between polymers and surfactants was recently reviewed by Robb (11) and surfactant association with proteins by Steinhardt and Reynolds (12). Polymer/surfactant interactions are highly dependent on the chemical nature of the polymer and the surfactant. In general, surfactants tend to associate with uncharged polymers in aggregates rather than individual surfactant molecules interacting with the macro-molecule. The ability of surfactants to form micelles is thought to be an important factor in the role of surfactant behavior in interactions with polymers. Individual surfactant... 

In recent years the investigation of polymer-surfactant interactions is a rapidly growing field of interest of modem colloid science [1-4], The mixtures and multilayer structures of polyelectrolytes and surfactants are widely used for industrial application to govern the wetting, adhesion, flotation processes and so on. 

Nizri G, Lagerge S, Kamyshny A, Major DT, Magdassi S. (2008) Polymer-surfactant interactions Binding mechanism of sodium dodecyl sulfate to poly(diallyldimethylammonium chloride). / Colloid Interface Sci 320 74-81. 

The discussion so far has been limited to polymer-surfactant Interactions in the bulk solution. In the section to follow, interactions at the air-liquid Interface are examined. 

This book on polymeric microemulsions is an attempt at a rapprochement of the methods and structures encountered in the two disciplines. The purpose of this book is to investigate polymer-polymer or polymer-surfactant interactions in solution leading to association structures with properties such as solubilization and anisotropy. These properties are useful in a wide variety of industries such as pharmaceutics, cosmetics, textiles, detergents, and paints. 

Bloor, D.M. HoUwarth, J.F. Wyn-Jones, E. Polymer/ surfactant interactions the use of isothermal titration calorimetry and EMF measurements in the sodium dodecyl sulphate/poly(A-vinylpyrrolidone) system. Langmuir 1995, 11, 2312-2313. 

Polymer surfactant interaction has been examined by using sodium 2-(N-dodecyIamino)naphthalene-6-sulphonate as a probe. Solute-solvent interaction of free base phthalocyanine has been examined in both polyethylene and polystyrene by the effect of pressure on spectroscopic hole burning s Fluorescence has been used to indicate the onset of aggregation in water soluble polymers s interaction of pyrenylmethyltributylphosphonium bromide with single strand polynucleotides , and the interaction of indole compounds with synthetic polyelectrolytes. ... 

Goddard ED. Polymer—surfactant interactions. Part I. Uncharged water-soluble polymers and charged surfactants. In Goddard ED, Ananthapadmanabhan KP, eds. Interactions of Surfactants with Polymers and Proteins. Boca Raton, FL CRC Press, 1993 123-169. 

The solubilization of the HMHEC in the surfactant was attributed to the interactions between surfactant micelles and polymer-bound hydrophobes. The effect of pH on polymer-surfactant solution viscosity was explained in terms of charge effects at the surface of the surfactant micelles. Steiner (13) proposed that at pH levels above or below the isoelectric point, the surfactant has a net charge on the head groups that causes repulsion within a single micelle. This repulsion leads to a relatively open micelle-aqueous phase interface through which polymer-bound hydrophobes can enter and experience stable polymer-surfactant interactions. These interactions anchor the polymer chains in an extended configuration. 

Polymer-surfactant interactions are the basis for the rheological behavior of MHAPs. Other surfactant-polymer systems have previously been investigated. One example is the interaction of surfactants with polymers such as poly(ethylene oxide), which results in greater solution viscosities than with the polymer alone (e.g., ref. 25 and references therein). The interaction of surfactants or latexes with hydrophobically modified water-soluble polymers has also been shown to produce unique rheology (2, 5, 26, 27). In these systems, the latex particles or the surfactant micelles serve as reversible cross-link points with a hydrophobic region of a polymer molecule in dynamic association with a latex particle or surfactant micelle (27). 

Polymers and surfactants are used together sometimes to obtain desirable effects. Polymer-surfactant interactions in solution and at the interfaces can change the interfacial properties of the solid directly or indirectly. It is shown that depending on the nature of the polymer and the surfactant, polymers can affect flotation of quartz by affecting the adsorption of the surfactant on it [7]. 

Figure 3, Reproducibility of high-throughput screening methods for cellulosic polymer-surfactant interaction contour phase diagrams,...

ATTRACTIVE POLYMER-SURFACTANT INTERACTIONS DEPEND ON BOTH POLYMER AND SURFACTANT... 

From this discussion, it is thus clear that a number of factors influence polymer-surfactant interactions. However, we can define three categories of surfactant binding to polymers, as follows ... 

Hydrophobic interactions are important in all three cases but there are important differences. In case 1, the normal surfactant-surfactant hydrophobic interaction is very similar to what applies in the absence of polymer while the attractive polymer-surfactant interaction is due to electrostatics. In case 2, there is a weak hydrophobic polymer-surfactant attraction (and an even weaker polymer-polymer attraction) and a partial elimination of an unfavourable surfactant-surfactant electrostatic repulsion. In case 3, there are strong... 

FIGURE 14.5. In some polymer-surfactant interactions there is evidence for the formation of micelle-like or hemimicelle aggregates of surfactant molecules along the polymer chain—something like a string of pearls. ... 

FIGURE 14.7. If an aqueous polymer-surfactant interaction occurs via the surfactant tail, the resulting complex will generally exhibit modified solution characteristics, usually reflecting a greater interaction with water and an expanded chain conformation. 

FIGURE 14.8. If a polymer-surfactant interaction occurs via the head group, the polymer will often exhibit solution characteristics reflecting a smaller, more compact configuration, even to the point of precipitation. 

FIGURE 14.12. Polymer-surfactant interactions are important in many areas of polymer science and technology, especially emnlsion polymerization. In snch processes surfactants and micelles perform several dnties snch as emulsification of monomers (a), solnbihzation of growing oUgomeric free radical chains (b), and stabilization of growing and final polymer particles (c). 

The striking difference of behavior between SDS and TTAB as far as changes of CMC and 3 are concerned suggest that the polymer-surfactant interaction occurs at the level of the surfactant ionic head group and does not involve the surfactant alkyl chain. This is turn means that the penetration of the polymer in the micelle will be restricted to the head group region, with little if any at all, penetration of the polymer in the micelle hydrophobic interior. Thus, the polymer surfactant interaction can be looked at as an adsorption of the polymer chain on the micelle surface. ... 

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