Excluded Volume Interaction
The ideal chain model assumes that polymer segments can overlap with each other as if the chain were a phantom chain. In reality, two segments cannot occupy the same space at the same time. This interaction between segments is called the excluded volume interaction.
The simplest formulation of excluded volume is the self-avoiding random walk, a random walk that cannot repeat its previous path. A path of this walk of N steps in three dimensions represents a conformation of a polymer with excluded volume interaction. Because of the self-avoiding nature of this model, the number of possible conformations is significantly reduced. The radius of gyration is generally larger than that of the ideal chain.
Read more about this topic: Polymer Physics
Famous quotes containing the words excluded, volume and/or interaction:
“Reasoning from the common course of nature, and without supposing any new interposition of the Supreme Cause, which ought always to be excluded from philosophy; what is incorruptible must also be ingenerable. The soul, therefore, if immortal, existed before our birth: And if the former existence noways concerned us, neither will the latter.”
—David Hume (1711–1776)
“Thy commandment all alone shall live
Within the book and volume of my brain
Unmixed with baser matter.”
—William Shakespeare (1564–1616)
“The act of putting into your mouth what the earth has grown is perhaps your most direct interaction with the earth.”
—Frances Moore Lappé (b. 1944)