Orderly arranged NLO materials based on chromophore-containing dendrons on exfoliated layered templates.
Three chromophore-containing dendrons were intercalated into montmorillonite layered silicates via an ion-exchange process. Enlarged d spacings ranging from 50 to 126 A were achieved for these novel organoclays. After the organoclays were blended with a polyimide, the steric bulkiness of the dendrons and the interaction between dendron and polyimide resulted in an ordered morphology. The orderly arranged nanocomposites were characterized by a UV-visible spectrophotometer, a variable-temperature infrared spectrometer, and electro-optical modulation. The dendrons in layered silicates were capable of undergoing a critical conformational change into an ordered structure, indicated by the drastic changes of interlayer distances at certain packing densities. Electro-optical coefficients increased sharply from 0 to 6 pm/V while the conformational change occurred. Furthermore, the addition of a polyimide capable of interaction-induced orientation was found to exert an enhancing effect on the degree of the noncentrosymmetric alignment.
Chen
Yung-Chung
YC
Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan.
Juang
Tzong-Yuan
TY
Wu
Tzong-Ming
TM
Dai
Shenghong A
SA
Kuo
Wen-Jang
WJ
Liu
Ying-Ling
YL
Chen
Franklin M C
FM
Jeng
Ru-Jong
RJ