Light-responsive wires from side-on liquid crystalline azo polymers

The pioneering work of Professor de Gennes in the field of liquid crystalline polymers and elastomers is outlined with an emphasis on artificial muscles. To illustrate the presentation, results on light-responsive nematic liquid crystalline elastomer fibres are reported. Two kinds of light-responsive wires were fabricated from an azobenzene-containing liquid crystalline copolymer with, or without cross-linking. Cross-linked wires were obtained by the reaction between the hydroxyl groups of the liquid crystalline copolymer and the diisocyanate groups of the cross-linker. The wires showed light-responsive bending towards the direction of the incident UV light at room temperature. Uncross-linked wires, drawn from the pure azobenzene copolymer, presented the same UV light-induced bending properties.