Reversible white-light actuation of carbon nanotube incorporated liquid crystalline elastomer nanocomposites

Nanoparticle-Liquid Crystalline Elastomer Composites

“…al. ultrasonicated the reaction mixture with SWNTs for 2 min, but aggregated SWNTs are still present in the material as can be seen with the naked eye [63].…”

“…Secondly, the addition of nanoparticles can increase the stiffness of the material, reducing the macroscopic elasticity (as has also been shown for other polymer systems). Li et al [63] also verified that the tensile strength of the CNT-LCE nanocomposites is significantly higher than those of neat LCEs. In addition, the rigidity of anisotropic nanoparticles that are aligned in LCEs may prevent the LCE matrix from undergoing full shape changes along the alignment axis during heating.…”

“…In a recent case, the authors only reported the actuation of one sample with 0.3 wt% SWNTs. The length decreased from 4 cm to 2.9 cm [63]. However, no comparison was described between different CNT loadings and the neat LCE.…”

“…SWNTs were also observed to precipitate out of the reaction mixture, and to aggregate severely during centrifugation. To avoid the formation of such layers, the first cross-linking can be performed by molded casting instead of centrifugation [63]. Yang et al [62] also used the casting method to prepare homogeneous SWNT-LCE nanocomposite.…”

“…However, when there is a higher amount of surfactant used to help the CNT dispersion, there is another mesophase transition at around 50 °C because of phase separation with the LCE matrix. Recently, it was reported that the addition of pristine SWNTs without any dispersant could induce a larger decrease in the transition temperature: from 82 to 63 °C for the sample with 1.8 wt% SWNT [63], probably due to phase separation between the CNT aggregates and the LCE matrix (nanotube demixing). In contrast, the SWNT-LCE composite prepared with conjugated polymers as a dispersant were rather inhomogeneous [69,70].…”