Polydispersity Subject

History. Starting from the ID point statistics of Zernike and Prins [116] J. J. Hermans [128] designs various ID statistics of black and white rods. He applies these models to the SAXS curves of cellulose. Polydispersity of rod lengths is introduced by distribution functions, / , (,r)108. Hermans describes the loss of correlation along the series of rods by a convolution polynomial . One of Hermans lattice statistics is namedparacrystalby Hosemann [5,117]. Hosemann shows that the field of distorted structure is concisely treated by the methods of complex analysis. A controversial subject is Hosemann s extension of ID statistics to 3D [63,131,227,228],... 

To substantiate the credibility of the newly developed method, a polydisperse system with f(M) known in advance was subjected to an equilibrium sedimentation experiment. Then the new computation-ori-... 

To perform this verification three narrow fractions of linear polystyrene denoted as A, B, and C were investigated to determine their molecular weights. This task was accomplished by applying velocity as well as equilibrium sedimentation. In addition, these three individual fractions were combined according to a known weight ratio into a new polydisperse sample denoted as P. Sample P was also subjected to equilibrium sedimentation. All samples were investigated in cyclohexane at 35°C (near the 0 temperature) see Table I. 

A.W. Chow, and G.G. Fuller, The rheo-optical response of rod-like chains subject to transient shear flow. Part I Model calculations on the effects of polydispersity, Macromolecules 18, 786 (1985) A.W. Chow, G.G. Fuller, D.G. Wallace and J.A. Madri, The rheo-optical response of rod-like chains subject to transient shear flow. Part II. Two-color flow birefringence measurements, Macromolecules 18,793 (1985) A.W. Chow, G.G. Fuller, D.G. Wallace and J.A. Madri, The rheo-optical response of rod-like shortened collagen protein to transient shear flow, Macromolecules, 18, 805 (1985). 

Dilute suspensions Subject to quenching at high colloid loads Little/no sample prep Poor resolution for polydisperse suspensions... 

Fontenot and Schork [ 140] studied the miniemulsion polymerization of methyl methacrylate using hexadecane as the costabihzer. A portion of their results are shown in Table 4. Polydispersities are listed for macroemulsion, and miniemulsions subjected to varying durations of sonication, at two levels of initiator. In this and all cases following, the macroemulsions and miniemulsions were made from the same recipe, but with the costabihzer left out of the macroemulsion. The miniemulsions and macroemulsions were polymerized by the same procedure except that the sonication was ehminated for the macroemulsions. It may be seen that at both initiator levels, the macroemulsion is slightly more narrow than some of the miniemulsions, but broader than others. An estimate of the standard deviation of the polydispersity measurement is given as 0.01-0.02, and may be applied to all of the polydispersity data reported. With this standard deviation estimate, it may be seen that the differences in polydispersity between the macro- and miniemulsions are not hkely to be significant. 

Landfester et al. [ 143] studied the miniemulsion polymerization of styrene using hexadecane as the costabilizer. When styrene miniemulsions were subjected to varying sonication times (see Table 5), very similar trends are seen as for the MMA miniemulsions. The particle size and the polydispersity of miniemulsion droplets rapidly polymerized after sonication either do not depend on the amount of the costabihzer, or are very weak functions of the amount of costabilizer (see Table 6). It was found that doubhng the amount of costabilizer does not decrease the radius nor have any effect on the polydis-... 

Bending moduli can in principle be obtained for two types of systems (i) extended, flat surfaces or interfaces, the subject matter of this section, and (ii) surfaces that are already strongly curved, and for which y is zero or extremely low, such as in vesicles or micro-emulsions. For instance such moduli can be inferred from shape fluctuations, from the Kerr effect (sec. 1.7.14] or from polydispersity using some scattering technique. We repeat that this type of measurement is often ambiguous because the bending contributions to the Helmholtz energy can only be estimated when all other contributions are accurately known. 

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