Sun, HaonanHaonanSunLührs, LukasLukasLührsChang, Wei-CheWei-CheChangShi, ShanShanShi2025-09-032025-09-032025-08-09Acta materialia 298: 121393 (2025)https://hdl.handle.net/11420/57214Hierarchical nanoscale network materials have gained increasing interest over the last decade attributing to their enhanced functional and mechanical performance, combined with reduced density. However, investigations into their Poisson's ratio, a key fundamental mechanical property, remain lacking. In this work, monolithic hierarchical nanoporous gold with tunable structure size and solid volume fraction were prepared via a two-step electrochemical dealloying method. By using in-situ digital image correlation technique, we measured their elastic and plastic Poisson's ratios during macroscopic compression. The effects of solid fraction, upper level ligament size and strain were explored systematically. We found that both the elastic and plastic Poisson's ratios are independent of the upper level ligament size and compressive strain. Notably, we introduced a novel scaling law of elastic Poisson's ratio with solid fraction in hierarchical nanoscale network materials and verified it experimentally. This study addresses a knowledge gap in the mechanics of hierarchical nanoscale network materials, offering a comprehensive understanding of their structure–mechanical property relationships. This insight provides a foundation for the design of novel materials and the optimization of their functional and mechanical properties.en1873-24532025Elsevierhttps://creativecommons.org/licenses/by/4.0/Hierarchical structureMechanical propertiesNanoporous metalsPoisson's ratioScaling lawTechnology::620: Engineering::620.1: Engineering Mechanics and Materials ScienceJournal Articlehttps://doi.org/10.15480/882.1583110.1016/j.actamat.2025.12139310.15480/882.15831Journal Article