Polymers at surfaces

Mixtures of polymers at surfaces provide the interesting possibility of exploring polymer miscibility in two dimensions. Baglioni and co-workers [17] have shown that polymers having the same orientation at the interface are compatible while those having different orientations are not. Some polymers have their hydrophobic portions parallel to the surface, while others have a perpendicular disposition. The surface orientation effect is also present in mixtures of poly(methyl methacrylate), PMMA, and fatty acids. 

The dynamics of polymers at surfaces can be studied via dynamic light scattering (DLS), as described in Section IV-3C. A modification of surface DLS using an evanescent wave to probe the solution in a region near the interface has... 

Even from those first remarks it is evident that our knowledge of polymers at surfaces and interfaces depends largely on analytical techniques. They should yield information on chemical composition, density, roughness, chain conformation, end distribution etc. across the interface with subnanometer resolution. In Sect. 2... 

This chapter is concerned with the application of liquid state methods to the behavior of polymers at surfaces. The focus is on computer simulation and liquid state theories for the structure of continuous-space or off-lattice models of polymers near surfaces. The first computer simulations of off-lattice models of polymers at surfaces appeared in the late 1980s, and the first theory was reported in 1991. Since then there have been many theoretical and simulation studies on a number of polymer models using a variety of techniques. This chapter does not address or discuss the considerable body of literature on the adsorption of a single chain to a surface, the scaling behavior of polymers confined to narrow spaces, or self-consistent field theories and simulations of lattice models of polymers. The interested reader is instead guided to review articles [9-11] and books [12-15] that cover these topics. 

Computer simulations of confined polymers have been popular for several reasons. For one, they provide exact results for the given model. In addition, computer simulations provide molecular information that is not available from either theory or experiment. Finally, advances in computers and simulation algorithms have made reasonably large-scale simulations of polymers possible in the last decade. In this section I describe computer simulations of polymers at surfaces with an emphasis on the density profiles and conformational properties of polymers at single flat surfaces. 

In contrast to the considerable attention focused on the behavior of athermal polymers at surfaces, there are very few simulation studies that have investigated the... 

There have also been a number of simulations of more realistic models of polymers at surfaces [65-77], The behavior of these more realistic models of polymers is similar to that of the model systems discussed above with no real surprises. Of course, the use of realistic models allows a direct comparison with experiment. For example, surface forces apparatus measurements [78] show that in some branched alkanes the force is a monotonic rather than oscillatory function of the separation. This is a surprising result because these branched alkanes pack quite efficiently (in fact they crystallize under some conditions), and this would imply that the surface forces should be oscillatory. Several... 

The last decade has seen active research in the implementation of liquid state methods to the behavior of polymers at surfaces or confined in small pores. 

E. Eisenriegler, Polymers at Surfaces, World Scientific, New York, 1993. 

There have been a number of studies of polymers at surfaces, as illustrated in Figure 8, including some that have been tethered [10, 122-137]. Also in this category are the polymer-clay composites after the previously paired platelets have been sufficiently separated to be independent of one another. Such exfoliated arrangements are shown in Figure 9. 

At separations of a few molecular diameters, the solvation force due to the specific structure of the confined liquid, can be substantial. Polymers at surfaces can be used to stabilize disperions by steric interaction. 

One of the main problems when writing a textbook is to limit its content. We tried hard to keep the volume within the scope of one advanced course of roughly 15 weeks, one day per week. Unfortunately, this means that certain topics had to be cut short or even left out completely. Statistical mechanics, heterogeneous catalysis, and polymers at surfaces are issues which could have been expanded. 

RJones, R. Richards, Polymers at Surfaces and Interfaces , Cambridge University Press (1999)... 

Interplay of attractive surface contacts and loss of configurational entropy 25 suggest that the properties of polymers at surfaces can be different from those in bulk. The analysis of the intensity autocorrelation requires evaluation of Eq. (10) without the assumptions that particles are independent and that averaging over... 

Jones, R.A.L. and Richards, R.W., Polymers at surfaces and interfaces, Cambridge University Press, Cambridge, 1999. 

Polymers at Surfaces and Interfaces, Faraday Discuss Chem. Soc., 98 1994 p 98... 

Frisch, H. L Simha, R., Statistical mechanics of flexible high polymers at surfaces. The Journal of Chemical Physics, 27(3), pp. 702-706 (1957). 

Several important areas relating to polymers at surfaces and interfaces are not discussed in this book. Almost nothing is said about crystalline polymers. Many engineering polymers are semi-crystalline and the nature of the interface between crystalline and amorphous phases in these materials has generated much debate and some rancour, into which the authors have no desire to venture. Concerning the nature of the surface of a crystalline polymer, beyond the results of a few experiments described in section 2.6 almost nothing is yet known. 

This text deals with the behaviour of polymers at surfaces and interfaces from a fundamental point of view. It covers in an integrated way both current experimental results, and the most important theoretical approaches to understanding these findings. 

Polymers at surfaces and interfaces/Richard A.L. Jones and Randal W. Richards, p. cm. 

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