Extended Data Fig. 6: Cycled strain-stress response upon gradually inreasing maximum strain.

We subject a commercial rubber band (a-c) and a ground state red-retroreflecting CLCE fibre made from LCO1 (d-f) to repeated strain-stress cycles at gradually increasing maximum strain, the speed being constant throughout the experiment. For the rubber band, we continue up to the point of rupture, whereas the CLCE fibre is strained only up to ϵ_xx = 2. Diagrams a/d show the applied strains ϵ_xx as a function of experiment time whereas b-c/e-f show the hysteresis behavior of σ_xx(ϵ_xx), with ϵ_xx-axis scaling adapted to the rubber band (b/e) and to the CLCE fibre (c/f), respectively. We find qualitatively similar behavior, although the hysteresis of the rubber band for strains exceeding the initial linear regime actually is larger than that of the CLCE fibre under the corresponding straining conditions. We note that the breaking stress \({\sigma }_{xx}^{max}\) for the rubber band here is only about 1/3 of that in Extended Data Fig. 5, although the breaking strain is comparable (\({\epsilon }_{xx}^{max}\approx 5.5\) here compared to 6.3 in Extended Data Fig. 5). This suggests that plastic deformation starts setting in during the cycles at gradually increasing maximum strain, leading to different breaking stress compared to the single increasing straining until break in Extended Data Fig. 5. For the CLCE fibre, the maximum \({\epsilon }_{xx}^{max}=2\) corresponds to \({\sigma }_{xx}^{max}\approx 12\) MPa which is about 20% higher than in Extended Data Fig. 5 for the same strain. We attribute this difference primarily to the slight variability between individual fibres in our non-automated CLCE fibre production.