合成了3种丙烯酸酯封端的取代苯甲酸以及其分别与4, 4′-联吡啶和反式吡啶基乙烯自组装形成的双氢键液晶,采用傅立叶红外光谱(FTIR)和核磁共振法(~1H-NMR)表征化合物的结构,使用偏光显微镜(POM)以及差示扫描量热仪(DSC)研究氢键液晶复合体的相转变行为.结果表明,在刚性液晶基元中引入氟原子会增加氢键液晶分子的宽度和降低分子的长径比对液晶材料的性能有很大影响,如降低氢键液晶的熔点以及清亮点等.另外,在柔性链末端引入丙烯酰氧基以及增加液晶基元的长度则会增加液晶分子的长度和规整性,提高氢键液晶复合体的相转变温度.
Three kinds of acryloxy-capping substituted benzoic acid compounds were synthesized and characterized;the corresponding symmetric hydrogen-bonded liquid crystals (H-boned LCs) based on 4, 4'-bipyridine (BP) or 4-((E)-2-(pyridin-4-yl)vinyl)pyridine (DPE) were prepared. The structure of precursors as well as the H-bond structures were confirmed by the ~1H nuclear magnetic resonance (~1H-NMR) and by Fourier transform infrared spectroscopy (FTIR). The mesogenic behavior of the H-bonded complexes was demonstrated by the polarizing optical microscopy (POM) and the differential scanning calorimetry (DSC). It was found that the fluoro substituent on the mesogenic core made the molecular width increased and thus the aspect ratio of the molecular decreased, therefore it could weaken the mesogenic behaviors of the H-bonded LCs such as decreasing the melting point as well as the clear point. Additionally, the introduction of terminal acryloxy group and the increase of induced rigid core could enhance the molecular length and regularity, resulting in the increase of phase transition temperatures of the complexes.
参考文献
| [1] | Kato T,Mizoshita N K,ishimoto K.Functional liquid-crystalline assemblies:Self-organized soft materials[J].Angew.Chem.Int.Edit,2006,45(1):38-68. |
| [2] | Kato T.Self-assembly of phase-segregated liquid crystal structures[J].Science,2002,295(5564):2414-2418. |
| [3] | Kato T,Frechet J M J.A new approach to mesophase stabilization through hydrogen bonding molecular interactions in binary mixtures[J].J.Am.Chem.Soc.,1989,111(22):8533-8534. |
| [4] | 魏强,原小涛,张立培,等.(+)-4-(2-甲基丁基)-4'-羧基联苯二聚体的相变研究[J].液晶与显示,2007,22(4):378-381. |
| [5] | Mallia V A,Das S.Synthesis and studies of some cholest-5-en-3-ol-(3b)[4-phenylpyridylazo] carbonate-containing supramolecular hydrogen-bonded mesogens[J].Liq.Cryst.,2001,28(2):259-264. |
| [6] | Schadt M.Liquid crystal materials and liquid crystal displays[J].Annu.Rev.Mater.Sci.,1997,27(1):305-379. |
| [7] | 李娟利,李建,杜渭松,等.含氟三环类液晶单体的介晶性研究[J].液晶与显示,2009,24(1):9-14. |
| [8] | 张兴,唐洪,杨增家.二氟甲氧基苯酚酯类液晶的合成[J].液晶与显示,2008,23(4):409-411. |
| [9] | 黄梅,陈建华,陶晓春,等.含氟反式环己基联苯液晶的合成[J].液晶与显示,2007,22(2):124-128. |
| [10] | 胡明刚,安忠维,李建.侧向邻二氟取代联苯类液晶的相变研究[J].液晶与显示,2007,22(2):151-155. |
| [11] | Guittard F,Taffin de Givenchy E,Geribaldi S,et al.Highly fluorinated thermotropic liquid crystals:an update[J].J.Fluorine Chem.,1999,100(1-2):85-96. |
| [12] | Huh I K,Kim Y B.Fluoro-isothiocyanated liquid crystal materials with high dielectric anisotropy and voltage holding ratio[J].Japan.J.Appl.Phys.,2002,41:6466-6470. |
| [13] | Wei Qiang,Shi Lin,Yuan Xiao-tao,et al.Synthesis and phase behaviour of hydrogen-bonded liquid crystalline complexes of allyloxybenzoic acid compounds with 4,4′-bipyridine[J].Liq.Cryst.,2007,34(7):855-860. |
| [14] | He Wan-li,Pan Guo-hui,Yang Zhou,et al.Wide blue phase range in a hydrogen-bonded self-assembled complex of chiral fluoro-substituted benzoic acid and pyridine derivative[J].Adv.Mater.,2009,21(20):2050-2053. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%