Reptation

Summary

Reptation is the snake-like motion of a long polymer chain in a dense entangled melt or gel. The surrounding chains confine each chain to a tube along its own contour, and the chain can only move by sliding along this tube. The model is due to de Gennes. It predicts that the time a chain needs to leave its tube grows like the cube of its length. It also predicts that the diffusion coefficient of the chain falls like the inverse square of its length. It is the basis of the tube theory of the flow of polymer melts.