Synthesis and polymerization of a chiral liquid crystal diacrylate exhibiting smectic A* and C* phases

The alignment and cross-linking of chiral liquid crystal (LC) phases has be en used to generate ordered noncentrosymmetric polymer networks with a vari ety of interesting optical and transducer properties. Examples of intrinsic ally chiral LC diacrylates which exhibit chiral smectic phases are rare bec ause of the difficulties associated with the design of such monomers. We ar e presenting the stereospecific synthesis and subsequent photopolymerizatio n of a chiral smectic diacrylate which is derived from (S)-ethyl lactate. T his monomer exhibits an enantiotropic smectic A* phase from 49 to 71 degree s C upon heating at 0.5 degrees C/min and from 71 to 39 degrees C upon cool ing at the same rate. The smectic A* phase of the chiral monomer can be hom eotropically and homogeneously aligned and subsequently photopolymerized to yield highly uniform, noncentrosymmetric polymer films of predefined symme try. Upon rapid cooling at 5 degrees C/min, the monomer also exhibits a met astable, monotropic ferroelectric smectic C* phase from approximately 35 to 33 degrees C. The cross-linking of this metastable phase will also be disc ussed.