freely jointed chain

in polymers
https://doi.org/10.1351/goldbook.F02517
A hypothetical @L03546@ molecule consisting of infinitely thin rectilinear segments uniform in length; each segment can take all orientations in space with equal @P04855@, independently of its neighbours. For models in which the segments are not all uniform in length, the name 'random-walk chain' has been used.
Source:
Purple Book, 1st ed., p. 50 [Terms]