Preparation of new carbosilane dendrimers having terminal mesogens and investigation of their liquid crystal characteristics

Both of a series of new second generation carbosilane dendrimers having a different number of branches (Me(n)G 2-Mesogen, n=1, 2, 3) and a novel carbosilane dendrimer having an increased length of methylene chain from the core to the second generation (Gradient G 2-Mesogen) with terminal cyanobiphenyl mesogens were prepared. The characterization of the dendrimers was carried out by using differential scanning calorimetry (DSC) and optical polarizing microscopy. All the dendrimers showed smectic A phase. The ranges of the smectic A phase and the texture size of Me(n)G 2-Mesogen were increased with increasing the number of branches. The behavior of phase transition temperature and the texture size of Gradient G 2-Mesogen were similar to those of Me(n)G-2 Mesogen.