Directional Liquid Transport Textiles: Performance Characterization and Application-Specific Optimization

Directional liquid transport (DLT) is a useful and efficient strategy for liquid transport in nature and in numerous wearable, separation, and energy-related applications. Recent advances in surface-chemistry modification and hierarchical textile structuring have enabled unprecedented control over through-thickness liquid transport, while multimodal characterization approaches have expanded the quantitative assessment of fluid migration across fibrous systems. Although DLT textiles share common features, including asymmetric wetting, capillary-driven liquid migration, and one-way transport, their characterization and optimization priorities vary with the use scenario; differences in measurement methods and testing conditions further complicate the interpretation of reported metrics across studies. In this Review, we present an overview of performance characterization and application-specific optimization of DLT textiles, illustrating how testing methods, evaluation metrics, and practical requirements can guide the translation of laboratory materials toward real-use products. We compare representative gravimetric, optical, and electrical approaches, and discuss how these measurements can be interpreted under different testing conditions. We also highlight the importance of application-relevant testing conditions, standardized evaluation protocols, and long-term robustness, providing a framework for interpreting DLT performance and guiding the optimization of DLT textiles for practical use.