Polymeric surfactants interactions

PPO), and CO- and tri-block variations of these structures. Polymeric surfactants interact with the surface in very different ways than low molecular weight surfactants. In most cases, it is believed that the hydrophobic moiety of the surfactant binds to the surface, exposing the hydrophilic portion to the run buffer. Polymeric surfactants have the advantage in that they can form effective coatings at low concentrations however, they are typically not as stable as their low molecular weight counterparts. 

Further evidence for the theory of stabilisation due to enhanced intermolecu-lar surfactant interactions was presented recently [112]. Two different surfactants were employed to stabilise w/o HIPEs sorbitan monooleate, a monomeric surfactant, and a polymeric surfactant. Salt addition enhanced the stability of the HIPEs, but more so in the presence of the polymeric surfactant. Again, the interactions between the salt and the surfactant were held responsible. The polymer contained ionic groups, which enabled it to interact strongly with the salt sorbitan monooleate, however, possesses groups which can only participate in hydrogen-bonding. 

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. 

Interaction between Oil or Water Droplets Containing an Adsorbed Polymeric Surfactant Steric Stabilisation... 

As most nanoemulsions are prepared using nonionic and/or polymeric surfactants, it is necessary to consider the interaction forces between droplets containing adsorbed layers (steric stabilisation). As this was described in detail in Chapter 10, only a summary will be given here [15, 16]. 

HMHECs can be viewed as polymeric surfactants. They tend to interact with low molecular weight surfactants and thus modify solution viscosity. The viscosity changes, however, depend on the nature (nonionic or ionic) and concentration of the surfactant. The molecular behavior of HMHEC in the presence of various types of surfactants has been described by Gelman (10) and Steiner (13). 

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. 

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