Dynamics of the Synthetic Macromolecules

CH2 carbons have shown the existence of two components with different Ti values for each carbon. This Ti result is in accord with the previous Ti results for poly[(R)-3-hydroxybutyric acid] [P(3HB)] homopolymer and other P(3HB)-type random copolyesters. In previous papers, however, the assignment of the two components with different Ti values have been remained unsolved. By performing variable-temperature experiments and by comparing with the results 

and English, A. D., eds. NMR Spectroscopy of Polymers in Solution and in the Solid State (ACS Symposium Series 834) , Oxford Univ. Pr., 2003 

and Maiti, S. Editor(s) Maiti, S., Analysis and Characterization of Polymers, 2003, 71-84 

Whittaker, A. K., Editor(s) Simon, G. P. Polymer Characterization Techniques and Their Application to Blends, 2003,461-503 Spiess, H. W., Macromolecular Symposia, 2003,201, 85-88 Li, Jun Rajca, Andrzej Rajca, Suchada., Synthetic Metals, 2003,137,1507-1508 Komenda, Thomas Jordan, Rainer., Polymer Preprints American Chemical Society, Division of Polymer Chemistry), 2003,44, 986-987 

Ji-Ruo Feng, Ying Chen, Xin-Feng., Journal of Applied Polymer Science, 2003,89,811-816. 

---

For synthetic macromolecules, NMR has been the most powerful method to characterize and to investigate the relationship between the structure and the physical properties at the atomic level. In the field of synthetic macromolecules, NMR is used not only as the routine analytical method but also as the method that has infinite possibility. In this chapter, NMR applications are reviewed by categorizing primary structure, liquid crystal, characterization of the synthetic macromolecules, dynamics of the synthetic macromolecules, gels and crosslinking macromolecules and polymer blends and diffusion of the synthetic macromolecules. 

In this chapter, the papers devoted to NMR application to study synthetic polymers over a period from June 2011 through May 2012 have been reviewed. It includes analysis of primary structure of polymers such as tacticity, regioregularity, end group, sequence distribution (section 2), application of imaging, diffusion and solid-state NMR techniques to characterize the synthetic macromolecules (sections 3 and 4). Finally in section 5, papers devoted to dynamics and polymer blend of the synthetic macromolecules have been surveyed. 

Abstract Amphiphilic polymers have the ability to self-assemble into supramolec-ular structures of great complexity and utility. Nowadays, molecular dynamics simulations can be employed to investigate the self-assembly of modestly sized natural and synthetic macromolecules into structures, such as micelles, worms (cylindrical micelles), or vesicles composed of membrane bilayers organized as single or multilamellar structures. This article presents a perspective on the use of large-scale computer simulation studies that have been used to xmderstand the formation of such structures and their interaction with nanoscale solutes. Advances in this domain of research have been possible due to relentless progress in computer power plus the development of so-called coarse-grained intermolecular interaction models that encode the basic architecture of the amphiphUic macromolecules of interest. 

A further application of time-resolved fluorescence measurements is in the study of conformational dynamics of polymer chains in solution. Fluorescence anisotropy measurements of macromolecules incorporating suitable fluorescent probes can give details of chain mobility and polymer conformation (2,14). A particular example studied in this laboratory is the conformational changes which occur in aqueous solutions of polyelectrolytes as the solution pH is varied (15,16). Poly(methacrylic acid) (PMA) is known to exist in a compact hypercoiled conformation at low pH but undergoes a transition to a more extended conformation at a degree of neutralization (a) of 0.2 to 0.3 (1 6). Similar conformational transitions are known to occur in biopolymer systems and consequently there is considerable interest in understanding the nature of the structures present in model synthetic polyelectrolyte solutions. 

We have tried to present a unified picture of results obtained on the adsorptlon/desorptlon phenomena of both synthetic and biological polymers. It appears that proteins like albumin or fibrinogen do adsorb on many surfaces with little structural alterations at the global molecular level, while the structure of flexible polymers Is radically altered once the molecule Is trapped In the Interfaclal force field. Conversely, the slow turnover existing between surface and solution macromolecules was shown to be total with polyacrylamide, while only partial with proteins, especially with fibrinogen. Thus, flexibility and reversibility au e preserved In the adsorbed state, for synthetic polymers, even If the time-scale of the mole-culau dynamics Is considerably different from that In solution. For adsorbed proteins, however, the existence of a population of nonexchangeable molecules remains to be fully explained. 

For several decades, fluorescence spectroscopy has been one of the most frequently used techniques for studying the conformations and dynamics of synthetic and natural macromolecules. The versatility and broad applicability of fluorescence techniques for investigation of both static and dynamic properties of different systems stems from two grounds ... 

---