Structural studies of monodomain smectic-A liquid crystalline elastomers under applying mechanical fields parallel to the layer normal

Abstract

A smectic A polymer network having permanently, macroscopically uniformly aligned director and smectic layers is synthesized, which is completely optically transparent. By applying mechanical fields in the direction parallel to the layer normal the S_A-elastomer becomes opaque if the strain is beyond 3%. Moreover the modulus of the elastomer, that is large under small strain, changes to a small modulus above the strain of 3%. Obviously at this point the monodomain structure is broken down to change a polydomain structure. Strain depending X-ray measurements reveal that the broken layers are rotated by the mechanical field and regions exist having nematic like order between broken layers.