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From Rubinstein & Colby Polymer Physics

Here is a nice example of scaling: 3 different types of polymers, all normalized sround the entanglement molecular weight and viscosity at that molecular weight. From Rubinstein & Colby Polymer Physics. The best experiments do not match the reptation prediction exactly.

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From Rubinstein & Colby Polymer Physics

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  1. Here is a nice example of scaling: 3 different types of polymers, all normalized sround the entanglement molecular weight and viscosity at that molecular weight. From Rubinstein & Colby Polymer Physics

  2. The best experiments do not match the reptation prediction exactly. From Rubinstein & Colby Polymer Physics

  3. What has this got to do with our creep compliance plot? 12 decades of time!!!??? In a mechanical experiment??? From Rubinstein & Colby Polymer Physics

  4. From Rubinstein & Colby Polymer Physics

  5. It is easier for a camel to pass through the eye of a needle than for an octopus to escape a fishnet. From Rubinstein & Colby Polymer Physics Can you think of an experiment?

  6. No one knows if reptation really happens in solutions; these diffusion results from an obscure group in Baton Rouge suggest not. Figure 1: Diffusion of fluorescently tagged dextran in unlabeled d extran matrix of Mw = 2,000,000 Da. No Matrix (), 5% w/w Matrix (■), 10% w/w Matrix (), 15% w/w Matrix (), 20% w/w Matrix (○), and 25% w/w ().

  7. We are putting probe diffusion to work. This molecular weight distribution was obtained without GPC, without AF4, without any separation at all. Figure 5. Representative spectra calculated by CONTIN and chosen by the user showing the detection of FD20 and FD70 in a mixture. The weight percent of the matrix solutions was 0.25. Spurious peaks at low and high M not shown. Molecules were just put under a “speed gun” as they diffuse around In a constraining solution.

  8. GPC is actually LESS effective in this case. Figure 6: GPC-MALS separation of FD20 and FD70 (circles; two different injections are shown). Also shown are individual runs for FD20 (-) and FD70 (+).

  9. Rheology plays a role in figuring out why our “non-separation” method doesn’t work even better. Figure 7: Illustration of the change of G′ over the range of dextran matrix concentrations at oscillation frequencies 2 Hz (■), 5 Hz (●), 10 Hz (▲), 20 Hz ().

  10. This figure demonstrates the absence of a rheological plateau modulus in the measured frequency range for the matrix dextran. Figure 7: Example of storage modulus, G′, as a function of frequencies for different dextran matrix concentrations: w = 5% (■), 10%(▲), 15%(), 20%(○), and 25%()

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