Monodomain-aligned film

Moreover, the monodomain-aligned films of crosslinked PLCPs show anisotropic photoinduced bending behavior [28]. As shown in Figure 7.10, the photoinduced... 

FIGURE 7.9 Photoresponsive properties of monodomain homogeneously aligned films of crosslinked PLCPs and their plausible mechanism of photoinduced bending and unbending behaviors. Reproduced with permission from Reference 28. Copyright 2003 John WUey Sons, Inc. 

More recently Ikeda and Tsutsumi [113] have used a SCLC polymer, 49, in which all of the mesogens are photoactive, azoaryl groups. They irradiated (355 nm, Nd-YAG) surface aligned monodomain films of 49 in both the N phase at... 

Keller and coworkers synthesized monodomain nematic side-on elastomers containing azobenzenes (Components 18a,b) by photopolymerization with a near-infrared photoinitiator (Li et al., 2003). The photopolymerization was performed with aligned nematic azobenzene monomers in conventional LC cells. Thin films of these LCEs showed fast (less than 1 min) photochemical contraction of up to 18% upon irradiation with UV light and a slow thermal back-reaction in the dark (Fig. 3.22). 

As mentioned above, LC elastomers, especially LSCE with monodomain order, anisotropic LC networks, and gels, may be optimized to make a kind of smart material for molecular switching and piezoelectric or pyroelectric sensors, because of their sensitivity to environmental conditions (electric or stress fields, temperature, and radiation, etc.) and memory effect. Other applications include wave-guide, polarizers, optical filters, alignment, and compensation films for LCD displays. 

The concept of mechanical field induced orientation can easily be transferred to nematic elastomers with oblate chain conformation, i.e., side chain end-on elastomers with an even number of spacer atoms. In order to achieve a monodomain structure, a globally oblate chain conformation has to be established. This can be achieved by uniaxial compression or biaxial stretching of the polydomain elastomer which induces a uniform homeotropic alignment of the nematic director perpendicular to the film plane. Up to now, this orientaticMi technique has only been realized experimentally for chiral nematic elastomers [72]. 

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