Micelle - polymer interactions

Jucker, B. A., Harms, H. and Zehnder, A. J. B. (1998). Polymer interactions between bacterial cells and glass investigated using LPS micelles, Coll. Surf. B, 11, 33 15. 

We have little information on the way low molecular weight molecules and oligomers adsorb (19). Apparently below DP s of about 100 they lie flat on the surface for concentrations up to a monolayer of segments, then seem to form thicker islands of smectic or nematic structure. Ordered condensed mono, -di, -or multi-layers are primarily the arrangements of smaller, especially amphipa-tic molecules on liquid-liquid interfaces. Polymers are too large to adsorb, in the ordinary sense, on micelles but segments of linear polymers may act as nucleation centers for micelles of small molecules which probably is one of the mechanisms for the lipid-, or detergent-, polymer interaction. 

Polymers Interact with surfactants and mlcroemulslons In diverse. Interesting and technologically Important wavs(1.21. The mechanisms that are responsible for the Interactions Include the usual panoply of forces Involved In the interaction of any two different molecules lon-lon, lon-dlpole, dlpole-dlpole, and van der Waals forces all modulated by the presence of solvent and/ or other species such as dissolved salts. All may play a role. The special factors Involved in surfactant/polymer and polymer-/mlcroemulslon Interactions that form the basis for their particular interest lies in their tendencies to form a variety of supermolecular clusters and conformations, which In tuim may lead to the existence of separate phases of coexisting species. Micelles may form In association with the polymer, polymer may precipitate or be solubilized, mlcroemulslon phase boundaries may change, and so on. 

Physicochemical characterisation was characterised of self-assembled nanoparticles based on glycol chitosan-bearing 5p-cholanic acid and their surfactant activity . Fluorescence spectroscopy and pulsed field gradient NMR (PFG-NMR) revealed information concerning the polydispersity of micelle polymers - chiral polymeric surfactants developed over the past decade for use as chiral selectors in the analytical separation of enantiomers . The authors suggest that polydispersity is a crucial factor in understanding the chiral interactions of these species. 

Surfactant-polymer interactions, micelle formation, and chemical reactions in micellar solutions and microemulsions... 

Photochemistry, photophysics Solvent-solute interactions, dynamics of micelles, polymer structure and dynamics, characterization of excited states, excimer and exciplex formation Capability to provide information on rapid phenomena... 

Finally, we can briefly consider the effect of PVP on SDS micelles. We recall that the CMC and B changes upon addition of PVP suggested that this polymer interacts more strongly than POE with SDS. The results of Table I show that the value of I1/I3 at low C in the PVP-SDS system, is close to that in water. Also, the values of kg are small and they increase with C, contrarily to the POE-SDS system. These two facts suggest a specific interaction between PVP and pyrene which may keep pyrene exposed to water (large I1/I3), and slows down its diffusion in the micelle (small kg). More investigations on the PVP-SDS systems appear necessary before a definite conclusion can be drawn concerning this system. 

R. NAGARAJAN is currently Assistant Professor of Chemical Engineering at the Pennsylvania State University. He received his Ph.D. degree in 1979 from the State Unviersity of New York at Buffalo. His research interests focus on surfactants, their mechanism of action and their applications. He has published more than 30 papers in the areas of thermodynamics of micelles, vesicles, solubilization, enhanced oil recovery and surfactant-polymer interactions. 

In the last years large attention was devoted to the synthesis and characterization of SBA-16 material focusing the interest on the formation mechanisms of copolymer micelles which drive the organization of the final siliceous mesostructure. In this framework, the physico-chemical properties at the interface between silica and triblock E0106P070E0106 co-polymer in a SBA-16 material were investigated. In particular, the combination of IR spectroscopy with SS NMR allowed to obtain complementary information on how the surfactant co-polymer interacts with the SBA-16 surface silanols in the presence or absence of physisorbed water and to follow the evolution of the structural organization of the co-polymer, which depends on the hydration degree of the SBA-16 sample. 

The proceedings cover six major areas of research related to chemical flooding processes for enhanced oil recovery, namely, 1) Fundamental aspects of the oil displacement process, 2) Microstructure of surfactant systems, 3) Emulsion rheology and oil displacement mechanisms, 4) Wettability and oil displacement mechanisms, 5) Adsorption, clays and chemical loss mechanisms, and 6) Polymer rheology and surfactant-polymer interactions. This book also includes two invited review papers, namely, "Research on Enhanced Oil Recovery Past, Present and Future," and "Formation and Properties of Micelles and Microemulsions" by Professor J. J. Taber and Professor H. F. Eicke respectively. 

Abstract A molecular interaction model of nonionic polymer-surfactant complex formation was developed by modifying the free-energy expression of micelles for interaction with polymer segments. Using the small systems thermodynamics the composition of the surfactant aggregates with respect to the aggregation number, the number of polymer segments involved in the... 

As depicted in this chapter, specific structural and electronic properties of fluo-ropolymers have made them the polymers of choice to be used in SC-CO2. The study of different families of fluoropolymer demonstrated that, apart from the effect of polymer architecture and CO2 density, the lowering of polymer-polymer interactions appeared as the main critical parameter to improve polymer solubility. Moreover, the use of those polymers as building blocks to design macromolecular surfactants allows the successful formation of micelle-like structures or the formation of emulsions in the presence of additional water. Based on this knowledge, development of new fluoropolymer families will surely pave the way for the preparation of stable W/SC-CO2 emulsions with great promise for the development of environmental-friendly chemical processes in diverse fields of organic and inorganic synthesis and polymerization. 

Najaragan [25] has introduced a comprehensive thermodynamic treatment of surfactant/polymer interaction. The aqueous solution of surfactant and polymer was assumed to contain both free micelles and micelles bound to the polymer molecule. The total surfactant concentration, Xt, is partitioned into single dispersed surfactant, Xi, surfactant in free micelles, Xf, and surfactant bound as aggregates, Xb,... 

---