Wicking through complex interfaces at interlacing yarns

Hypothesis: Wicking flow in the wale direction of knit fabrics is slowed by capillary pressure minima dur-ing the transition at yarn contacts. The characteristic pore structure of yarns leads to an unfavorable free energy evolution and is the cause of these minima.Experiments: Time-resolved synchrotron tomographic microscopy is employed to study the evolution of water configuration during wicking flow in interlacing yarns. Dynamic pore network modeling is used based on the obtained image data and distributions of delay times for pore intrusion. Good agreement is observed by comparison to the experimental data.Findings: Yarn-to-yarn transition is found to coincide with slow water advance in a thin interface zone at the yarn contact. The pore spaces of the two yarns merge within this interface zone and provide a tran-sition path. A deep capillary pressure minimum occurs while water passes through the center of the interface zone, effectively delaying the wicking flow. A pore network model considering pore intrusion delay times is expanded to include inter-yarn wicking and reproduce the observed wicking dynamics.(c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Automated summary

The wicking flow in knit fabrics is slowed by capillary pressure minima during the transition at yarn contacts due to the characteristic pore structure of yarns. Experimental and modeling studies were conducted to investigate the water configuration evolution and the delay times for pore intrusion. The findings reveal that the water advance is slow in the thin interface zone at the yarn contact and a deep capillary pressure minimum occurs, effectively delaying the wicking flow. The pore network model successfully reproduces the observed wicking dynamics, including inter-yarn wicking.