Achiral flexible liquid crystal trimers exhibiting dark conglomerate phases with different porous structures

Abstract

We prepared a homologous series of achiral liquid crystal trimers in which two phenylpyrimidine units and one biphenyl unit were connected via flexible spacers, and investigated the phase transition behavior and the phase structure using polarized optical microscopy (POM), differentical scanning calorimetry, X-ray diffraction (XRD), and atomic force microscopy (AFM). All the trimers were found to exhibit nematic and dark conglomerate (DC) phases. The AFM measurements reveal that the DC phases have different porous structures depending on the alkyl spacer length.