Pelcovits Robert A, Meyer Robert B
Department of Physics, Brown University, Providence, Rhode Island 02912, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Sep;66(3 Pt 1):031706. doi: 10.1103/PhysRevE.66.031706. Epub 2002 Sep 23.
In a nematic gel, the appearance of nematic order is accompanied by a spontaneous elongation of the gel parallel to the nematic director. If such a gel is made chiral, it has a tendency to form a cholesteric helical texture, in which local elongation of the gel parallel to the nematic director is suppressed due to the requirement of elastic compatibility. We show that a conical helix in which the director makes an oblique angle with respect to the helix axis serves as an energy minimizing compromise between the competing tendencies for elongation and twisting. We find the dependence of the helical cone angle and pitch on the strength of the chirality, and determine the change in sample shape at the isotropic to cholesteric phase transition.
在向列型凝胶中，向列相序的出现伴随着凝胶沿与向列指向矢平行方向的自发伸长。如果使这种凝胶具有手性，它就会倾向于形成胆甾型螺旋织构，其中由于弹性相容性的要求，凝胶沿与向列指向矢平行方向的局部伸长受到抑制。我们表明，指向矢相对于螺旋轴呈倾斜角度的锥形螺旋是伸长和扭曲这两种相互竞争趋势之间能量最小化的折衷方案。我们发现螺旋锥角和螺距对手性强度的依赖性，并确定在各向同性到胆甾相转变时样品形状的变化。
