Polymer/surfactant systems interaction between polymers

Polymer-surfactant systems have found wide-spread practical applications, e.g., in paints, in pharmaceutical formulations, and in systems for enhanced oil recovery. Their practical importance and the fundamental intricacies in these systems have triggei extensive studies of the interactions between polymers and surfactants, and several reviews have appeared [1-6]. The sodium dodecylsulfate (SDS)-poly(ethylene oxide) (PEO) system has been particularily well studied, both by classical [7,8] and modem methods [9-12]. 

The interaction between polymer and surfactant could be investigated by the conductivity measurements. The electrical conductivity measurements are usually used to detect any changes in the solution behavior when an ionic surfactant is added to the aqueous solution. If there occurs any interaction, the solution conductivity is expected to change. Figure 13.7 shows the typical conductivity plots for pure ionic surfactant solution and a mixed polymer/ionic surfactant system. 

These are normally a gelled surfactant solution of well-defined associated structures, e.g. rod-shaped micelles (see Chapter 2). A thickener such as a polysaccharide may be added to increase the relaxation time of the system. Interaction between the surfactants and polymers is of great importance. 

Systems Where Interaction Between Polymer and Surfactant is Weak or Not Existent... 

Most examples of magnetoresponsive polymer systems involve noncovalent interactions between polymer chains and magnetic particles [125, 127, 128]. However, recent synthetic advances have facilitated covalent immobilization of polymer chains directly to the surface of magnetic particles. Pyun et al. have employed nitroxide-mediated radical polymerization (NMP) to prepare well-defined polymeric surfactants that stabilize magnetic nanoparticles. By casting nanoparticle... 

The interaction between polymers and surfactants and colloidal systems in general has gained interest in many fields in recent years due to... 

Interactions between polymers and surfactants have been widely investigated in the recent decades. The interaction may lead to a polymer-surfactant complex formation, which may have a significant influence on the system properties e.g. emulsification, colloidal stability, viscosity enhancement, gel formation, solubilization, and phase separation [Goddard 1993a Goddard 2002]. The properties and structure of surfactant-polymer complexes depend on the molecular characteristics of both the polymer and surfactant [Lindman Thalberg,... 

These include electrostatic interaction between the particles and interaction of particles with the fluid governed by their wettability, morphology and density (17-19) the extent of adsorption of the polymer and its influence on the interaction of particles, the orientation or configuration of the adsorbed polymers (and surfactant when it is present) and resultant interaction of adsorbed layers the hydrodynamic state of the system and its influence on the interaction of floes themselves. 

IPEC or hydrogen-bonded complexes may form not only between mutually interacting polymer blocks but also between a polymer block and low-MW molecules. Complexes between surfactants and block copolymers have been investigated for the formation of micelles. As illustrated by the work of Ikkala and coworkers [313], one of the major interests of these systems is that they combine two different-length scales of supramolecular organizations, i.e., the nanometer-scale organization of the (liquid) crystalline surfactant molecules and the ten-nanometer scale relative to block copolymers. This gives rise to the so-called hierarchical systems. The field of (block)... 

As with normal hydrocarbon-based surfactants, polymeric micelles have a core-shell structure in aqueous systems (Jones and Leroux, 1999). The shell is responsible for micelle stabilization and interactions with plasma proteins and cell membranes. It usually consists of chains of hydrophilic nonbiodegradable, biocompatible polymers such as PEO. The biodistribution of the carrier is mainly dictated by the nature of the hydrophilic shell (Yokoyama, 1998). PEO forms a dense brush around the micelle core preventing interaction between the micelle and proteins, for example, opsonins, which promote rapid circulatory clearance by the mononuclear phagocyte system (MPS) (Papisov, 1995). Other polymers such as pdty(sopropylacrylamide) (PNIPA) (Cammas etal., 1997 Chung etal., 1999) and poly(alkylacrylicacid) (Chen etal., 1995 Kwon and Kataoka, 1995 Kohorietal., 1998) can impart additional temperature or pH-sensitivity to the micelles, and may eventually be used to confer bioadhesive properties (Inoue et al., 1998). 

Attempts to correlate the adsorption data of other surfactants such as Alipal EP-110 and NaLS on the three latex surfaces in a similar manner failed because of the more complex and specific interactions observed in these systems. Equation 2 can adequately describe the adsorption data of surfactants at polymer/ water interfaces, provided that the free energy of the interface is related to the free energy of adsorption and there are no specific interactions between surfactant and interface (15). 

There are three chapters in this volume, two of which address the microscale. Ploehn and Russel address the Interactions Between Colloidal Particles and Soluble Polymers, which is motivated by advances in statistical mechanics and scaling theories, as well as by the importance of numerous polymeric flocculants, dispersants, surfactants, and thickeners. How do polymers thicken ketchup Adler, Nadim, and Brenner address Rheological Models of Suspensions, a closely related subject through fluid mechanics, statistical physics, and continuum theory. Their work is also inspired by industrial processes such as paint, pulp and paper, and concrete and by natural systems such as blood flow and the transportation of sediment in oceans and rivers. Why did doctors in the Middle Ages induce bleeding in their patients in order to thin their blood ... 

The effect of water soluble polymers on the phase behavior of the anionic mlcroemulslon system was studied as a function of surfactant H/L properties. The cloud point temperatures for the neat mlcroemulslons and those containing 1500 ppm HPAM, partially hydrolyzed polyacrylamide, and 1000 ppm Xanthan gum are given In figure 4. The addition of either xanthan blopolymer or HPAM results In an Increase In the cloud point temperature of the mlcreomulslon. Both polymers have similar Interactions with the mlcroemulslon. Again one observes a lipophilic shift of the mlcroemulslon system Indicative of a repulsive interaction between the polymer and these anionic surfactants. 

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