rigid chain

https://doi.org/10.1351/goldbook.RT06871
The rod-like chain of an MCPLC (main-chain polymer liquid crystal) with direct links between the mesogenic groups for which the persistence length is at least comparable with the contour length and much greater than the diameter.
Source:
PAC, 2002, 74, 493. 'Definitions of basic terms relating to polymer liquid crystals (IUPAC Recommendations 2001)' on page 505 (https://doi.org/10.1351/pac200274030493)