Liquid crystal elastomers: Influence of the orientational distribution of the crosslinks on the phase behaviour and reorientation processes

The influence of the crosslinking conditions on the phase behaviour and reorientation processes of nematic elastomers is investigated. Two series of elastomers with various network anisotropies crosslinked either in the nematic or in the isotropic state were investigated by means of IR-dichroism and stress-strain measurements. The experimental results clearly demonstrate that for nematic elastomers not only the coupling between the network anisotropy and the state of order has to be considered. It is shown that the influence of the crosslinks and their orientational distribution on the phase behaviour, the state of order as well as on director reorientation processes cannot be neglected.