低临界转换频率的双频驱动液晶分子的设计、制备及性能  

Design,preparation and properties of dual frequency liquid crystalline compounds with low crossover frequency

作　　者：王萌[1] 李辰悦 胡威[3] 肖久梅[4] 丁杭军[2] 张兰英[1] 杨槐[1] 

机构地区：[1]北京大学工学院,北京100871 [2]北京科技大学材料科学与工程学院,北京100083 [3]北京科技大学化学与生物工程学院,北京100083 [4]北京科技大学数理学院,北京100083

出　　处：《中国科技论文》2016年第6期595-600,共6页China Sciencepaper

基　　金：高等学校博士学科点专项科研基金资助项目(20120001130005);国家自然科学基金资助项目(51273022;51272026)

摘　　要：目前市售的双频驱动液晶材料存在临界转换频率高、驱动电压高、种类少等问题,限制了其在显示和光学器件上的应用。基于材料物理性能和分子结构的关系,通过改变分子末端基团种类、刚性环个数、侧链氟原子的取代位置和个数,设计并制备出9种双频驱动液晶分子。采用傅里叶红外光谱和核磁共振氢谱表征分子结构,通过差示扫描量热仪结合偏光显微镜表征相态及相变温度,最后采用阻抗分析仪测定化合物的介电常数、计算临界转换频率。实验结果表明,单一化合物的临界转换频率可降低至20.1kHz。另外,通过密度泛函理论对分子结构进行了模拟计算,发现理论计算结果与实验结果一致。The disadvantages of commercial dual frequency liquid crystals （DFLC） , such as high crossover frequency, high driving voltage and less species, limit their application in display and electro-optical devices. According to the relationship between property and molecular structure, nine kinds of DFLC molecules were designed and prepared by variation in terminal chain, rigid core, position and number of lateral fluorine substitution The molecular structures of these compounds were characterized by Fourier transform-infrared spectroscopy （FT-IR） and nuclear magnetic resonance spectroscopy （NMR）. The phase transition temperature and phase types were investigated by differential scanning calorimetry （DSC） and polarizing optical microscope （POM）. And dielectric constant and crossover frequency were measured by impedance analyzer. The pure molecular crossover frequency can be reduced to 20. 1 kHz. Moreover, the molecular structures of all the compounds were studied by using the theory of density functional theory （DFT） , and theoretical analysis consists with experimental results.

关 键 词：材料物理与化学 液晶 双频驱动 临界转换频率 

分 类 号：O753.2[理学—晶体学]