Questions from class - Lecture 6 Flashcards Preview

Polymer Physics > Questions from class - Lecture 6 > Flashcards

Flashcards in Questions from class - Lecture 6 Deck (6):
1

What is the definition of a "blob"? How is the chain conformation inside a blob?

A blob is segment of the polymer of size ksi in which the chain statistics inside is unperturbed.

2

How can the chain conformation be determined in a scattering experiment?

From measuring the scattering intensity of the same concentration for many angles, and extrapolating to theta -> 0. The slope of the curve will give information of the radius of gyration, which tells us something about the conformation.

3

What is dilute/semidilute/concentrated polymer solution?

Dilute: concentration so low that the polymer molecules are far from eachother.

Semidilute: concentration is so that the polymers just start to touch.

Concentrated: concentration is so high that there is lot of entanglement.

4

How does phase diagrams of polymer solutions and polymer blends look like?

Polymer solution: It is very asymmetric, and has a molar mass-dependent phase boundary.

Polymer blends: more symmetric than polymer solutions.

5

Which type of model is used to calculate the entropy of mixing?

A simple lattice model is used.

6

How does the entropy of mixing of a polymer blend compare to the one of a regular solution?

The entropy of mixing in a polymer blend is much lower than for a regular solution.