Poly(diphenylacetylene) Bearing Long Alkyl Side Chain via Silylene Linkage: Its Lyotropic Liquid Crystallinity and Optical Anisotropy
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- 作者：Giseop Kwak ; Masashi Minakuchi ; Toshikazu Sakaguchi ; Toshio Masuda ; Michiya Fujiki
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：July 24, 2007
- 年：2007
- 卷：19
- 期：15
- 页码：3654 - 3661
- 全文大小：340K
- 年卷期：v.19,no.15(July 24, 2007)
- ISSN：1520-5002
文摘
The liquid crystalline properties and optical anisotropy of poly(diphenylacetylene) bearing ann-octadecylsilane moiety in the side chain, poly(1-phenyl-2-p-{dimethyl-n-octadecylsilylphenyl}acetylene)(C18-PDPA), were investigated in detail. C18-PDPA exhibited unexpected smectic phase liquid crystallinityin highly concentrated aromatic organic solvents such as toluene, despite its extremely high molecularweight of 4.18 × 106 g/mol and a fairly wide polydispersity index of 2.5. This lyotropic liquid crystallinitywas derived from: a high molecular stiffness (expected from the high viscosity index of 
1.03), ahigh degree of intermolecular packing (the fractional free volume 0.16), and ultrahigh molecular weight.The two major absorption bands, located at 430 and 370 nm, are attributed to the 
-* transition parallelto the main chain and the localized -* transition with a charge-transfer characteristic among mesogenicrepeating units perpendicular to the main chain axis, respectively. C18-PDPA exhibited highly polarizedabsorption and fluorescence bands in a sheared film. The main chain axis of the polymer was alignedparallel to the shearing direction, whereas the long axis of the stilbene-like side group was perpendicularto the shearing direction.
1.03), ahigh degree of intermolecular packing (the fractional free volume 0.16), and ultrahigh molecular weight.The two major absorption bands, located at 430 and 370 nm, are attributed to the -* transition parallelto the main chain and the localized -* transition with a charge-transfer characteristic among mesogenicrepeating units perpendicular to the main chain axis, respectively. C18-PDPA exhibited highly polarizedabsorption and fluorescence bands in a sheared film. The main chain axis of the polymer was alignedparallel to the shearing direction, whereas the long axis of the stilbene-like side group was perpendicularto the shearing direction.