端基含36个4-硝基偶氮苯介晶基元的二代树状碳硅烷的液晶性研究  

Studies on Liquid Crystalline of Carbosilane Dendrimer of the Second Generation Containing Thirty-six 4-Nitroazobenzene Mesogenic Groups in Its Periphery

作　　者：张其震[1] 盛昕[1] 殷晓颖[1] 李光[2] 季怡萍[2] 

机构地区：[1]山东大学化学化工学院,济南250100 [2]中国科学院长春应用化学研究所,长春130022

出　　处：《高等学校化学学报》2004年第5期988-990,共3页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号 :2 98740 2 0 ;5 95 73 0 2 9);山东省自然科学基金(批准号 :Y95 B0 72 0 );中国科学院长春应用化学研究所高分子物理重点实验室基金资助

摘　　要：Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.

关 键 词：4-硝基偶氮苯 碳硅烷 液晶行为 树状化合物 

分 类 号：O634.41[理学—高分子化学]