Extensional Relaxation Times of Dilute, Aqueous Polymer Solutions
Extensional Relaxation Times of Dilute, Aqueous Polymer Solutions
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DOI：
10.1021/acsmacrolett.5b00393
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发表时间：
2015-07-01
影响因子：
7.015
通讯作者：
Sharma, Vivek
中科院分区：
文献类型：
--
作者：
Dinic, Jelena;Zhang, Yiran;Sharma, Vivek
我们表明，可视化和分析的毛细管驱动的变薄和夹断动态的柱状颈部在一个不对称的液体桥创建的滴到基板上，可以用于表征复杂流体的拉伸流变学。使用稀释的PEO水溶液的特定实例，我们示出了具有低剪切粘度η < 20 mPa.s和相对短的弛豫时间的弱弹性聚合物复杂流体的拉伸弛豫时间和拉伸粘度两者的测量，lambda <这些稀溶液中的弹性效应和拉伸弛豫时间的表征超出了标准几何中可测量的范围用于市售的剪切和拉伸流变仪（包括CaBER，毛细管破裂拉伸流变仪）。由于连接固着液滴到喷嘴的颈部的半径是光学检测的，并且粘弹性流体的拉伸响应的特征在于通过分析它们的弹性毛细管自减薄，我们将这种技术称为光学检测的弹性毛细管自减薄滴到基底上（ODES-DOS）拉伸流变学。
We show that visualization and analysis of capillary-driven thinning and pinch-off dynamics of the columnar neck in an asymmetric liquid bridge created by dripping-onto-substrate can be used for characterizing the extensional rheology of complex fluids. Using a particular example of dilute, aqueous PEO solutions, we show the measurement of both the extensional relaxation time and extensional viscosity of weakly elastic, polymeric complex fluids with low shear viscosity eta < 20 mPa.s and relatively short relaxation time, lambda < 1 ms. Characterization of elastic effects and extensional relaxation times in these dilute solutions is beyond the range measurable in the standard geometries used in commercially available shear and extensional rheometers (including CaBER, capillary breakup extensional rheometer). As the radius of the neck that connects a sessile drop to a nozzle is detected optically, and the extensional response for viscoelastic fluids is characterized by analyzing their elastocapillary self-thinning, we refer to this technique as optically-detected elastocapillary self-thinning dripping-onto-substrate (ODES-DOS) extensional rheometry.