Atomic force microscopic studies of the influence of stretching on thin oriented films of ferroelectric liquid crystalline elastomers

To analyze the impact of the molecular structure on the network formation i n ferroelectric liquid crystalline polymers, two copolymers are studied, wh ich are identical except for the molecular position of the cross-linkable g roup: (i) Polymer P1 with cross-linkable groups attached to the backbone vi a a short spacer and (ii) Polymer P2 with the cross-linkable group in termi nal position of a mesogenic side group. When mechanical stress is imposed o n thin films in homeotropic orientation through stretching, the two elastom ers react differently to the deformation, as seen by AFM imaging of the sur face topology: For Polymer P1, "intra-layer" cross-linking results in two d imensional networks in each backbone layer, separated by liquid-like FLC si degroup layers. As there are practically no vertical connections in this in tralayer network, no vertical distortions occur. In Polymer P2 a three dime nsional, "inter-layer" network is formed; the system reacts with a distorti on of the smectic layering.