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.