半花菁／氮冠（醚）交替LB多层膜的二阶光学非线性性质

对一种新型的，具有双脂链的盘状非活性分子氮冠（醚）（ＮＣ）ＬＢ膜进行了表征。小角Ｘ射线衍射（ＳＡＸＤ）结果表明：纯ＮＣ分子可以形成非常好的ＬＢ膜有序结构。将它与活性分子半花菁（ＤＡＥＰ）制备成Ｙ型交替多层膜，由于半花菁分子的单脂链（长尾）可以镶嵌在ＮＣ分子的双脂链之间，改善了多层膜的结构有序性及稳定性，从而得到二次谐波强度随层数的变化在１￣１１６双层范围内显示出较理想的平方关系。通过二次谐波的测量

Second Order Optical Nonlinear Properties of Interleaving Hemicyanine/Nitrogencrown LB Multilayers

A novel bifat chain amphiphilic molecule nitrogencrown (NC) in Langmuir Blodgett (LB) films was characterized. The NC was adopted as an inert material for fabrication of optical nonlinear LB multilayers. The second harmonic generation (SHG) intensity increased quadratically with the bilayer number (up to 116 bilayers) in Y type hemicyanine (DAEP)/NC interleaving LB multilayers due to improvement of the structural properties by insertion of the long hydrophobic tail of DAEP molecules between two chains of NC molecules. The second order nonlinear susceptibility χ(2) ZXX (-2ω; ω, ω)=18 pM V -1 (or 4.4×10 -8 esu) was obtained by measuring SHG from the DAEP samples. The NC molecule has attractive features as a matrix material in fabrications of LB multilayers made from optically nonlinear molecules with hydrophobic long tails.