Cooperative polymerizations

Hunter (60) reported a self-assembled open polymer formed by a zinc porphyrin bearing one para-aniline substituent at the meso position. The ortho- and mela-analogs discussed above form closed dimers, but the geometry of the para-derivative precludes this, and polymerization is the only alternative (76, Fig. 31). Although the dilution experiments could be fitted to a non-cooperative polymerization model with a pairwise association constant (K = 190 M 1) practically identical to that found for simple aniline-zinc porphyrin complexes (K = 130 M 1), broadening of the 4H NMR spectrum at high concentrations is characteristic of oligomerization. 

Fisher JRE, Rosenbachbelkin V, and Scherz A. Cooperative Polymerization of Photosynthetic Pigments in Formamide-Water Solution. Biophys. J. 1990 58 461-470. 

The preparation of this review was supported in pint by the NSF Center for Polymeric Interfaces and Macromolecular Assemblies (CP1MA) under cooperative agreement DMR-9400354. 

Sharkey, W. H. Polymerizations Through the Carbon-Sulphur Double Bond. VoL 17, pp. 73-103. Shimidzu, T. Cooperative Actions in the Nucleophile-Containing Polymers. Vol. 23, pp. 55-102. Slichter, W. P. The Study of High Polymers by Nuclear Magnetic Resonance. VoL 1, pp. 35-74. Small, P. A. Long-Chain Branching in Polymers. VoL 18,pp. 1-64. 

In a film, the cooperative effort of the different molecular motors, between consecutive cross-linked points, promotes film swelling and shrinking during oxidation or reduction, respectively, producing a macroscopic change in volume (Fig. 18). In order to translate these electrochemically controlled molecular movements into macroscopic and controlled movements able to produce mechanical work, our laboratory designed, constructed, and in 1992 patented bilayer and multilayer103-114 polymeric... 

Miller J.A., Speckhard T.A., Homan J.G., and Cooper S.L. Monte Carlo simulation study of the pol3mier-ization of polyurethane block co-polymers. 4. ModeUng of experimental data. Polymer, 28, 758, 1987. Speckhard T.A., Miller J.A., and Cooper S.L., Monte Carlo simulation study of polymerization of polyurethane block co-pol3miers. 1. Natural compositional heterogeneity under ideal polymerization condition, Macromolecules, 19, 1550, 1986. 

Kauss, H. and Swanson, A.L. (1969) Cooperation of enzymes responsible for polymerization and methylation in pectin biosynthesis. ZJ aturforsch. 24 28-33. 

Membranes UF membranes consist primarily of polymeric structures (polyethersulfone, regenerated cellulose, polysulfone, polyamide, polyacrylonitrile, or various fluoropolymers) formed by immersion casting on a web or as a composite on a MF membrane. Hydrophobic polymers are surface-modified to render them hydrophilic and thereby reduce fouling, reduce product losses, and increase flux [Cabasso in Vltrafiltration Membranes and Applications, Cooper (ed.). Plenum Press, New York, 1980]. Some inorganic UF membranes (alumina, glass, zirconia) are available but only find use in corrosive applications due to their high cost. 

The value of EM for a cooperative self-assembled structure provides a measure of the monomer concentration at which trivial polymeric structures start to compete, and therefore EM represents the upper limit of the concentration range within which the cooperative structure is stable (Scheme 2). The lower limit of this range is called the critical self-assembly concentration (csac) and is determined by the stoichiometry of the assembly and the strength of the non-covalent binding interactions weaker interactions and larger numbers of components raise the csac and narrow the stability window of the assembly (8). Theoretical treatments of the thermodynamics of the self-assembly process have been reported by Hunter (8), Sanders (9), and Mandolini (10). The value of EM is lowered by enthalpic contributions associated with... 

Chemical reactions, like phase transitions are driven by interparticle interactions that give rise to fluctuations and cooperative effects. The closest parallel of a phase A transition is with a polymerization reaction, such as... 

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