Preparation and characterization of novel carbosilane dendrimers carrying mesogens

A series of new carbosilane dendrimers carrying cyanobiphenyl derivatives w as prepared starting from the tertiary core molecule, triallylphenylsilane. The phase transition of the dendrimers depends on the dendrimer generation , and the spacer lengths were investigated by using differential scanning c alorimetry (DSC) and an optical polarizing microscope. All of the dendrimer s prepared exhibited smectic A phases. The phase behavior on the phase-tran sition pattern of the DSC curve and the texture appearances of G2-mesogen(5 ) carrying twenty-seven mesogens were observed to be similar to that of the reported G2 dendrimer prepared starting from the quarternary core molecule , tetraallylsilane, carrying thirty-six mesogens.(4)