Dendromesogens: Liquid crystal organizations versus starburst structures

The synthesis and the liquid crystalline behavior of a novel series of poly (amidoamine) (PAMAM)-dendrimer derivatives is described. The series consist s of five new compounds that contain 4, 8, 16, 32, and 64 peripheral mesoge nic ester units attached to the 0-, 1-. 2-, 3-, and 4-generation of poly(am idoamine) (PAMAM), respectively. These five compounds exhibit a smectic A m esophase, for which a structural model is proposed that is valid for severa l generations of dendrimers. This model is based on a structural characteri zation which mainly consists of X-ray diffraction studies. The molecules of these compounds exhibit a high degree of plasticity and tend to adopt the most convenient shape to afford liquid crystalline behavior. The mesogenic units form parallel aggregations that give rise to the smectic structure.