Questions from class - Lecture 9 Flashcards Preview

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What is the intrinsic viscosity and how is it related to the molecular weight of the polymer?

The intrinsic viscosity is the solute's contribution to the viscosity of a solution. It is defined:

[eta] = lim eta_sp / c, as c -> 0

eta_sp = eta_r - 1 = (eta - eta_s / eta_s)

where eta is the solution viscosity, eta_s is the solvent viscosity and eta_r is the relative viscosity (eta/eta_s). eta_sp is called the specific viscosity.


What is subdiffusive motion of the chain, and why does it appear?



Which polymer systems are described by de Gennes' reptation model? How do the time of reptation and viscosity scale with molecular weight?

It describes linear polymers.

The time of reptation scales with M^3. The viscosity scales (from experiments) with M^3,4.