Alignment of Red Poly[dodecadyin-1,12-diol-bis(4-butoxycarbonyl-methyl-urethane)] in Couette Flow

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• 作者：Donglin Xie ; Yalin Wei ; Greg G. Qiao ; Dave E. Dunstan
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：September 1, 2016
• 年：2016
• 卷：120
• 期：34
• 页码：9173-9179
• 全文大小：428K
• 年卷期：0
• ISSN：1520-5207

文摘

The flow-induced alignment of red poly[dodecadyin-1,12-diol-bis(4-butoxycarbonyl-methyl-urethane)] (poly-4BCMU) in chloroform/toluene solution is reported. Absorption spectra have been measured over a range of shear rates in an optically transparent quartz Couette cell. The measured spectra show that the poly-4BCMU structure stays the same in flow, while the measured absorbance anisotropy is attributed to the flow-induced particle alignment in the red form poly-4BCMU solutions. A limiting orientation at shear rates >50 s^–1 is observed. Numerical simulations show that the spectral changes are consistent with the rodlike poly-4BCMU particle having an aspect ratio of 2.9. The dichroic ratio of 1.9 interpreted from the data indicates that the individual poly-4BCMU chains do not aggregate amorphously in the rodlike conformation, rather they show a preferred orientation along the long axis of the prolate aggregates.