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在聚合物滴滴的散布和干燥过程中,状图案沉积

Ahmed M Othman¹, Andreas S Poulos², Ophelie Torres²

¹Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Dr, Cambridge, CB3 0AS, UK. afr10@cam.ac.uk.

|October 10, 2023

概括

乙醇滴中的聚烯 (PVP) 由于微量水引起的表面张力梯度,形成了状的图案. 马兰戈尼力,而不是蒸发,驱动这种不稳定性在高能量表面.

科学领域:

流体动力学流体动力学
材料科学是一种材料科学.
表面化学表面化学

背景情况:

在乙醇中的聚烯 (PVP) 滴在高能表面干燥时呈现出独特的状图案.
观察到两种不同的传播模式,形成统一的薄膜.
聚合物积聚在滴滴边缘,受微量水的影响,产生表面张力梯度.

研究的目的:

调查PVP-乙醇水滴中贝不稳定的背后的机制.
确定影响滴滴传播和薄膜形成的主导因素.
了解表面张力梯度和基板性质的作用.

主要方法:

在各种基板上对滴滴传播和薄膜形成的实验观测.
操纵环境条件 (例如,乙醇蒸汽和) 来控制蒸发.
分析微量水和聚合物度对不稳定性的影响.
使用长波进化方程的理论建模.

主要成果:

由微量水和马兰戈尼力驱动的表面张力梯度,是皮不稳定的首要原因.
蒸发对不稳定波长的影响微不足道.
基板表面能量和表面张力梯度的大小是关键因素.
临界重叠度决定了过渡到环状形态.
不稳定是通过移除水来抑制的,这证实了马兰戈尼部队的作用.

结论:

由表面张力梯度引起的马兰戈尼力,是PVP-乙醇滴滴中状不稳定的原因.
观察到的不稳定性主要是由流体动力学和表面化学,而不是简单的蒸发.
理论模型准确地预测了不稳定的波长,验证了拟议的机制.

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