Liquid crystal acrylate-based networks: polymer backbone–LC order interaction

Thermomechanical modeling of the thermo-order–mechanical coupling behaviors in liquid crystal elastomers

“…This director reorientation is more or less uniform across the whole sample. In fact, another kind of stripe pattern rotation of the director is also reported in the experiments Finkelmann, 1995, 1998;Talroze et al, 1999;Zhang and Heiney, 2006). Under perpendicular or oblique stretch, in different domains the director rotates clockwise or anti-clockwise to avoid a large macroscopic shear.…”

“…In the experiment of Talroze et al (1999), both the stripe pattern rotation and the uniform rotation were found. Which one happened depended on the length width ratio of the sample.…”

“…This continuous manifold corresponds to the non-convex energy function with infinite continuous minima, which implies the existence of deformation paths that do not require the application of forces (Carlson et al, 2002). In the work of Roberts et al they reported the continuous rotation of the director under oblique stretch (Roberts et al, 1997;Talroze et al, 1999;Zhang and Heiney, 2006). This director reorientation is more or less uniform across the whole sample.…”

“…Moreover, even when the samples were of the same dimensions and cut from the same batch of free-standing elastomer film, Zhang and Heiney (2006) also observed both these two phenomena. More factors may affect the preference of the director rotation, for example, the shape of the sample (Talroze et al, 1999), the crosslinking density (Kundler and Finkelmann, 1998) and the angle between the initial director and the stretch (Zhang and Heiney, 2006).…”

“…The stress-strain relation and the elastic modulus change with temperature (Wermter and Finkelmann, 2001;Finkelmann et al, 2001a). If the stretch is perpendicular or oblique to its director, the LC mesogens may transit to the stretch direction abruptly (Mitchell et al, 1993) or continuously (Roberts et al, 1997;Talroze et al, 1999;Zhang and Heiney, 2006) under different conditions. A stripedomain instability was also reported under perpendicular stretch Finkelmann, 1995, 1998;Zhang and Heiney, 2006).…”