What is "reptation"

Reptation \Rep*ta"tion\ (r?p-t?"sh?n), n. [L. reptatio, from reptare: cf. F. reptation.] (Zo["o]l.) The act of creeping.

n. 1 creep 2 (context physics English) A creeping thermal motion of entangled linear polymers

Reptation is the thermal motion of very long linear, entangled macromolecules in polymer melts or concentrated polymer solutions. Derived from the word reptile, reptation suggests the movement of entangled polymer chains as being analogous to snakes slithering through one another. Pierre-Gilles de Gennes introduced (and named) the concept of reptation into polymer physics in 1971 to explain the dependence of the mobility of a macromolecule on its length. Reptation is used as a mechanism to explain viscous flow in an amorphous polymer. Sir Sam Edwards and Masao Doi later refined reptation theory. Similar phenomena also occur in proteins.

Two closely related concepts are Reptons and Entanglement. A repton is a mobile point residing in the cells of a lattice, connected by bonds. Entanglement means the topological restriction of molecular motion by other chains.