The synthesis and mesomorphic properties of a new series of five-ring esters composed of banana-shaped molecules are reported. The homologues containing n-dodecyloxy, n-tetradecyloxy and n-hexadecyloxy terminal chains exhibit a smectic phase while that with an n-octadecyloxy chain shows a two-dimensional structure. The structures of the mesophases have been determined by X-ray diffraction studies. Interestingly both these mesophases exhibit ferroelectric properties. The electro-optical switching characteristics have been investigated using both triangular-wave and d.c. electric fields. Ferroelectricity is clearly demonstrated in both the mesophases by bistable switching behaviour.
报告了一系列由香蕉形分子组成的新型五环酯的合成和介形特性。含有正
十二烷氧基、正
十四烷氧基和
正十六烷氧基末端链的同系物呈现出胶凝相,而含有
正十八烷氧基链的同系物则呈现出二维结构。这些介相的结构是通过 X 射线衍射研究确定的。有趣的是,这两种介相都具有
铁电特性。利用三角波和直流电场对电光开关特性进行了研究。通过双稳态开关行为,两种介相都清楚地证明了
铁电性。