Chiral phase-coexistence in compressed double-twist elastomers

We adapt the theory of anisotropic rubber elasticity to model cross-linked double-twist liquid crystal cylinders such as exhibited in biological systems. In mechanical extension we recover strain-straightening, but with an exact expression small twist-angle limit. compression, observe coexistence between high and low twist phases. Coexistence begins at compressive strains is robustly observed for any cross-links general functions -- disappears large angles. Within region, significant compression allowed constant stress. Our results are qualitatively consistent previous observations swollen or compressed collagen fibrils, indicating that this phenomenon may be readily accessible experimentally.