Polymeric surfactants solution properties

Pfannemtiller et al. showed that it is possible to obtain carbohydrate-containing amphiphiles with various alkyl chains via amide bond formation. For this, mal-tooligosaccharides were oxidized to the corresponding aldonic acid lactones, which could subsequently be coupled to alkylamines [128-136]. Such sugar-based surfactants are important industrial products with applications in cosmetics, medical applications etc. [137-139]. The authors were also able to extend the attached mal-tooligosaccharides by enzymatic polymerization using potato phosphorylase, which resulted in products with very interesting solution properties [140, 141]. 

The surfactant properties of polymeric silicone surfactants are markedly different from those of hydrocarbon polymeric surfactants such as the ethylene oxide/propylene oxide (EO/PO) block copolymers. Comparable silicone surfactants often give lower surface tension and silicone surfactants often self-assemble in aqueous solution to form bilayer phases and vesicles rather than micelles and gel phases. The skin feel and lubricity properties of silicone surfactants do not appear to have any parallel amongst hydrocarbon polymeric surfactants. 

Chemical modification of hydroxyethylcellulose or hydroxypropylcellulose with long-chain hydrocarbon alkylating reagents, such as C8-C24 epoxides or halides, has been reported to yield novel water-soluble compositions exhibiting enhanced low-shear-rate solution viscosities and polymeric surfactant properties [ 104,105]. Patents have also been issued for water-soluble phosphonomethylcellulose and phosphonomethylhydroxyethylcellulose [106,107]. 

Copolymers 59 [181] and terpolymers 60 [182] were synthesized by micellar copolymerization and characterized with respect to their molecular and solution properties. The subject of further investigations was the interaction with low molecular weight surfactants [181,183]. Another interesting use was made of hydrophobized sulfopropylammonio monomers as surface-active monomers (or surfmers ) [184]. Their use in emulsifler-free emulsion polymerizations [185] reduced the water uptake and improved the mechanical stability of the resulting filmed latexes. 

The first section of this chapter describes the solution properties of polymers, and this is followed by a general classification of polymeric surfactants. Examples are provided of polymeric surfactants and polyelectrolytes that are used as dispersants and emulsifiers. 

Incorporation of long-chain hydrocarbon hydrophobes into a cellulose ether backbone leads to an interesting new class of polymeric surfactants. Their enhanced solution viscosity can be explained in terms of intermolecular associations via the hydrophobe moieties. Entropic forces cause the polymer hydrophobes to cluster to minimize the disruption of water structure. The same thermodynamic principles that are used to explain the micellization of surfactants can be applied to explain the solution behavior of HMHEC. HMHECs interact with surfactants that modify their solution viscosities. The chemical nature and the concentration of the surfactant dictate its effect on HMHEC solution behavior. The unique rheological properties of HMHEC can be exploited to meet industrial demands for specific formulations and applications. 

NVP-HRAM). We examined both synthetic variables and the aqueous (brine) viscometry of the products. The NVP-RAM polymers were synthesized by terpolymerization of acrylamide (AM)f N-octylacrylaxnide (RAM), and N-vinylpyrrolidone (NVP) in water with AIBN initiator and SDS surfactant. Since NVP is a moderately good solvent for N-octyl acrylamide, only low levels of SDS are required. The effects of polymerization variables on product solution properties was studied. 

In many instances it is found that complexes of surfactant with polymer solubilize various materials at lower total surfactant concentrations and have a greater solubilizing capacity (e.g., solubilized molecules per molecule of surfactant) than a surfactant solution alone. Unfortunately, our present state of knowledge in this area is not sufficient to allow quantitative predictions about the potential solubilizing properties of surfactant-polymer complexes based solely on chemical composition, although it is known that the effectiveness of a given combination depends on the nature of the polymeric component and the polymer surfactant ratio. 

Surfactants are used in a wide variety of applications such as ore flotation, cleaning, polymerization processes, and pharmaceuticals and agriculture. The usual role for the surfactant is to modify interfacial properties, whether they be liquid/liquid, solid/liquid, or gas/liquid interfaces. To be effective in any of these applications, however, the surfactant must adsorb strongly at the interface. In addition to its concentration at the interface, the conformation of the surfactant at the interface is also an important factor. While the influence of solution properties such as concentration, ionic strength, and pH on surfactant adsorption are well known, the properties of the other phase also exert a significant influence. 

Other applications of alcohol alkoxylates also include textile lubricants, agricultural chemicals, rinse aid formulations, and personal care products. Polyoxyethylene block copolymers exhibit properties similar to surfactants, such as the presence of micelles in aqueous solutions, micelle structure, and association number, and are therefore termed polymeric surfactants. These diverse subsets of nonionic surfactants are unique and offer several advantages in manufacturing, and they could be designed for specific uses and applications. A complete Surfactant Science Series volume dedicated to the chemistry, physicochemical properties, applications, and toxicity was published in 1996. Because of these beneficial attributes, alcohol ethoxylates and alcohol alkoxylates are the most important nonionic surfactants in terms of volume usage in consumer products. 

In Chapter 3, the solution and surface properties of a relatively new class of material, namely, polymeric surfactants, are illustrated in some detail using Flory-Huggins theory and current polymer-adsorption theory. This is followed by a discussion of the phenomenon of steric stabilization of suspended particles and how it is affected by the detailed structure of the stabilizing polymeric species. It concludes with a discussion of the stabilization of emulsions by interfacial and bulk theological effects, and presents closing comments on multiple emulsions. 

This chapter, will begin with a brief description of polymeric surfactants and their solution properties, followed by a description of the fundamental principles of using polymeric surfactants for stabilization of emulsions (as well as suspensions), starting with a section on the adsorption and conformation of these molecules at the interface. This is followed by a section on stabilization of dispersions by polymeric surfactants. Particular... 

To understand the solution behavior of polymeric surfactants of the block-and-graft type, it is essential to consider the solution properties of the more simple homopolymers. The solution behavior of homopolymers was considered in the thermodynamic treatment of Flory and Huggins. 

This chapter described the basis principles involved in stabilization of dispersions by polymeric surfactants. The first part described polymeric surfactants and their solution properties. The second part described the adsorption of polymeric surfactants and their conformation at the interface. The methods that can be applied to determine the adsorption and conformation of polymeric surfactants were briefly described. The third part dealt with the stabilization mechanism produced using polymeric surfactants. Two main repulsive forces were considered. The first arises from the unfavorable mixing of the chains on close approach of the particles or droplets, when these chains are in good solvent conditions. This is referred to as mixing or osmotic repulsion. The second force of repulsions... 

Interactions between surfactant anions and the polymeric cation not only influence the solution properties of the two compounds, but also affect the nature of their deposition on the fiber surface. Averages (16 measurements each) of advancing wettabilities of fibers treated with 15 solutions of JR-400 containing increasing concentrations of sodium lauryl sulfate show high levels of deposition with low substantivity up to the critical micelle concentration (CMC) of the lautyl sulfate, at which point wettabihty decreases, especially after the third immersion. This decrease to values below that of the imtreated fiber indicates a reorientation of the surfactant-polymer complex resulting in a hydrophobic fiber surface. 

Polymer surfactant, poly(Na-acrylamidoalkanoate)s [73] at a low concentration, was observed to increase its viscosity with dilution. Moreover, the intrinsic viscosity is strongly influenced by the presence of electrolytes. The viscosity of this polymerized surfactant decreased markedly with the addition of NaCl, indicating that the electrostatic repulsions between the charged head are suppressed, which causes a contraction of the polymer chain in the solution. The mixture of this surfactant with alum [74] was found to show coagulant properties in the same manner as cationic polyamines. 

Emulsion polymerization of pyrrole was also used to prepare blends of polypyrrole with a poly(alkyl methacrylate) [95]. A chloroform solution of a poly-(alkyl acrylate) and pyrrole was dispersed in an aqueous surfactant solution generating an emulsion. An aqueous solution of an oxidant was added to the emulsion with stirring, polymerizing pyrrole. The precipitated blend could be hot pressed in the form of films with conductivities of 6-7Scm . The curve for the variation of the conductivity of the blend with the oxidant/pyrrole ratio shows a maximum at a ratio of two with subsequent decrease. However, the yield increases to nearly 100% up to a ratio of four. The percolation threshold is approximately 10 wt% of pyrrole. The type and the concentration of the surfactant also affect the yield and conductivity. The mechanical properties of the blend depends on the number of carbons in the alkyl chain of the insulating polymer host. The strain at break of hot-pressed films increases and the stress at break decreases in the direction methyl, ethyl, butyl (Figure 18.3). This is an example where the mechanical properties of the conductive blend could be tailored according to the alkyl substituent in the poly(alkyl methacrylate) used in its preparation. 

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