School of Engineering and Materials Science, Queen Mary University of London , London E1 4NS, United Kingdom.
School of Engineering, University of Portsmouth , Portsmouth PO1 3DJ, United Kingdom.
Langmuir. 2017 Oct 31;33(43):12072-12079. doi: 10.1021/acs.langmuir.7b02982. Epub 2017 Oct 17.
Understanding the penetration of liquids within textile fibers is critical for the development of next-generation smart textiles. Despite substantial research on liquid penetration in the plane of the textile, little is known about how the liquid penetrates in the thickness direction. Here we report a time-resolved high-resolution X-ray measurement of the motion of the liquid-air interface within a single layer textile, as the liquid is transported across the textile thickness following the deposition of a droplet. The measurement of the time-dependent position of the liquid meniscus is made possible by the use of ultrahigh viscosity liquids (dynamic viscosity from 10 to 2.5 × 10 times larger than water). This approach enables imaging due to the slow penetration kinetics. Imaging results suggest a three-stage penetration process with each stage being associated with one of the three types of capillary channels existing in the textile geometry, providing insights into the effect of the textile structure on the path of the three-dimensional liquid meniscus. One dimensional kinetics studies show that our data for the transplanar penetration depth Δx vs time do not conform to a power law, and that the measured rate of penetration for long times is smaller than that predicted by Lucas-Washburn kinetics, challenging commonly held assumptions regarding the validity of power laws when applied to relatively thin textiles.
了解液体在纺织纤维内的渗透对于下一代智能纺织品的发展至关重要。尽管已经对纺织平面内的液体渗透进行了大量研究，但对于液体在厚度方向上的渗透方式却知之甚少。在这里，我们报告了一种对单层纺织品内液体-空气界面运动的时间分辨高分辨率 X 射线测量，该测量是在液滴沉积后，液体在穿过纺织品厚度时进行的。通过使用超高粘度液体（动态粘度比水大 10 到 2.5×10 倍），实现了对液体弯月面随时间变化位置的测量。这种方法由于渗透动力学较慢而能够进行成像。成像结果表明，渗透过程存在三个阶段，每个阶段都与纺织品几何形状中存在的三种毛细通道类型之一有关，为了解纺织品结构对三维液体弯月面路径的影响提供了线索。一维动力学研究表明，我们的平面穿透深度Δx 随时间变化的数据不符合幂律关系，并且长时间测量的穿透速率小于 Lucas-Washburn 动力学预测的值，这对幂律在相对较薄的纺织品上的适用性提出了挑战。
