Nematic elastomers: The influence of external mechanical stress on the liquid‐crystalline phase behavior

Abstract

The influence of external mechanical stress on the nematic-isotropic phase transformation of nematic elastomers was investigated. The experimental results of IR-dichroism measurements in the nematic phase and stress-optical measurements in the isotropic phase are in good agreement with the theoretical predicitions of the phenomenological Landau-de Gennes theory. This is for the first time that a significant influence of an external field on the nematic-isotropic phase transformation temperature and on the nematic order parameter S has been proved.

X-Ray Diffraction Studies on the Phase-Transformational Behavior of a Smectic Liquid-Crystalline Elastomer Composed of Chiral Mesogens

“…In addition, it is noteworthy that the directional-order still remains above the SmA-Iso phase transition temperature because of remaining local order arising from crosslinks. [14] Namely, the order parameter S is about 0.2 at 145 8C, here it is 25 degrees higher than the SmA-Iso phase transition temperature detected by DSC. Figure 5a shows the temperature dependence of layer spacing d L , which is obtained from the location of the smallangle peaks in the radial intensity profile shown in Figure 3b.…”

A Smectic A Liquid Single Crystal Elastomer (LSCE): Phase Behavior and Mechanical Anisotropy

“…[11] Stress, strain, temperature, and birefringence are measured simultaneously. The birefringence is determined by the phase shift of monochromatic light (He-Ne-laser, k = 632.8 nm) passing through the sample, applying the method of a rotating analyzer.…”

An Artificial Muscle with Lamellar Structure Based on a Nematic Triblock Copolymer

“…Recently, a muscle-like material has been generated using this kind of side-on nematic homopolymer. [15,20,21] Therefore, the side-on nematic monomer shown in Figure 2 was chosen to construct the N domain in the triblock copolymer. The amorphous rubber block was chosen to be a statistical copolymer, poly(n-butyl acrylate)-co-poly(2-hydroxyethyl acrylate).…”