静电纺丝聚合物溶液弹性的溶剂效应《ACS Polymers Au》

静电纺丝聚合物溶液弹性的溶剂效应

摘要

通过静电纺丝制造的超细纤维是先进纤维应用的领跑者，但要将超细纤维从潜在应用过渡到商业应用，需要更好地了解静电纺丝中聚合物溶液的行为，以便设计更复杂的纺丝涂料。在复杂流体中，存在改变自由表面流动的粘弹性应力和微观结构转变。这些可能在剪切流变学中看不到；因此，必须对拉伸流变行为进行深入分析。在这项工作中，我们使用滴在基底上的流变测量来表征静电纺丝中常用的四种聚合物溶液（低分子量和高分子量聚乙烯吡咯烷酮在甲醇和水中，以及聚氧乙烯和聚乙烯醇在水中）的静电纺丝涂料的拉伸粘度。我们将通过纤维形态表征的静电纺丝性与半稀和缠结聚合物溶液的拉伸流变性联系起来，并表明高表面张力溶剂需要更高的拉伸粘度和松弛时间才能形成光滑的纤维，而Deborah和Ohnesorge数是测定静电纺丝性的一种很有前景的方法。通过溶剂特性、粘弹性和静电纺丝性之间的这种联系，我们将能够设计出更复杂的纺丝涂料，适用于可穿戴电子产品、制药等领域。

关键词：静电纺丝, 拉伸流变, 超细纤维, 毛细管不稳定性

图1：用于研究的聚合物的化学结构 (A)PVP, (B)PVA, (C)PEO。

Solvent Effects on the Elasticity of Electrospinnable Polymer Solutions

Elena Ewaldz, Joshua Randrup, and Blair Brettmann*

Materials Science and Engineering, Georgia Institute of Technology, 711 Ferst Drive, Atlanta, Georgia 30332, United States

Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States

ACS Polym. Au 2022, 2, 2, 108–117

Publication Date: December 28, 2021

https://doi.org/10.1021/acspolymersau.1c00041

Abstract

Ultrafine fibers manufactured through electrospinning are a frontrunner for advanced fiber applications, but transitioning from potential to commercial applications for ultrafine fibers requires a better understanding of the behavior of polymer solutions in electrospinning to enable the design of more complex spinning dopes. In complex fluids, there are viscoelastic stresses and microstructural transitions that alter free surface flows. These may not be seen in shear rheology; therefore, an in-depth analysis of the extensional rheological behavior must be performed. In this work, we use dripping-onto-substrate rheometry to characterize the extensional viscosities of electrospinning dopes from four polymer solutions commonly used in electrospinning (low- and high-molecular-weight polyvinylpyrrolidone in methanol and water as well as poly(ethylene oxide) and poly(vinyl alcohol) in water). We link the electrospinnability, characterized through fiber morphology, to the extensional rheological properties for semidilute and entangled polymer solutions and show that high-surface-tension solvents require higher extensional viscosities and relaxation times to form smooth fibers and that the Deborah and Ohnesorge numbers are a promising method of determining electrospinnability. Through this tie between solvent characteristics, viscoelasticity, and electrospinnability, we will enable the design of more complex spinning dopes amenable to applications in wearable electronics, pharmaceuticals, and more.

KEYWORDS: Electrospinning, extensional rheology, ultrafine fibers, capillary instabilities

来源：《ACS Polymers Au》

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