CHEM 4214 Lecture Notes - Lecture 33: Reptation, Ideal Chain, Normal Mode

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25 Apr 2016
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Normal modes imagine a string --> different harmonics if you have long string vibrating in many ways, can decompose them into vibrational modes and then add them together to get final vibration. Each mode involves (n/p) segments p = 1, 2, , n p = 1 --> whole chain vibrates p = 2 --> half chain vibrates. Rouse model (assumes ideal chain --> simpler) draining. Each mode has its own relaxation time is largest relaxation of chain. Zimm model (don"t assume ideal chain) nondraining --> hydrodynamic coupling relaxation time is the most important thing we want to know about a polymer sample w/o sum, it"s maxwell model --> gives perfect exponential. For rouse model, (in analogy, ) single mode. For zimm model looks like above plot, but the slope of the asymptote is. Chem4212 polymers page 3 if low mw polymer melts concentrated polymer melts b/c there"s no solvent --> no solvent effect, no flow surrounding youneighbors screen hydrodynamic rxns.