溶于液晶的二向色性染料有序参数的研究

Study on the Order Parameters of Dichroric Dyes Dissolved in Liquid Crystals

研究了宾主盒的二向色性染料的有序参数(S)与其分子长度(l)、宽度等分子构型以及分子的偶极和诱导偶极的关系,发现S随l的增长而增大。当l增加到一定值时,有序参数增大缓慢,如果l超过液晶分子太大时,则出现下降趋势。而在平均分子长度为1.4 nm的E_7液晶中,染料分子长度达到2.30nm时,其有序参数将趋于饱和。染料分子的侧向取代基由于增加其分子宽度,也会使有序参数下降。宾主盒的有序参数随染料分子与液晶分子间偶极作用的增加而增大。宾主盒有序参数越大,其二色比越高,显示对比度一般也越高。

The relations among order parameters of dichroric dyes in guest-host cells, their molecular length and width, molecular dipole moment and induced dipole moment were studied. The order parameter (S) increases with length (l). When l increases to a certain value, the S increases slowly, if l of dye molecule is much longer than the l of liquid crystal molecule the S will tend to decrease. In E_7 (mean value of molecular length of the liquid crystal is 1.4nm), if dye molecular length reaches 2.3 nm, the S will approach saturation. Since the side substitution group increases its width the S will be decreased. The S of guest-host cell increases with the increase of dipole-moment between the molecules of the liquid crystal. The higher the order parameter of the G. H. cell is, the larger the dichroic ratio, generally, the higher its color contrast.