folded-chain crystal

in polymers
https://doi.org/10.1351/goldbook.F02475
A @P04737@ consisting predominantly of chains that traverse the crystal repeatedly by folding as they emerge at its external surfaces. The re-entry of the chain into the crystal is assumed to be adjacent or near-adjacent within the lattice.
Source:
Purple Book, 1st ed., p. 84 [Terms] [Book]