<p>Capillary networks are prevalent in nature and biology, playing a crucial role in systems like animal vasculature and plant capillaries, with broad applications in medicine and science. However, many aspects of how these networks regulate and control flow remain unresolved. While the basic principles of capillary networks and their functions are well understood, ongoing research seeks to uncover how these systems dynamically respond to environmental changes, adapt to varying conditions, and whether they retain a memory of past states. Developing a model system for capillary networks allows us to pose exciting new questions, such as: "Can capillary networks store memory?"</p><p>Building such a model presents two key challenges. First, the need to dynamically modify the nature of bonds within the networks and understand its impact on transport. Second, designing networks capable of evolving in response to external stimuli. Successfully addressing these challenges could transform our ability to actively control macroscale flow by manipulating local bonds within the networks.</p><p>Here, a novel experimental model of capillary networks is proposed, consisting of hundreds of interconnected liquid diodes. Like electrical diodes, these microscale surface structures direct liquid flow in specific directions while preventing reverse flow. However, under certain conditions, liquid diodes may fail, permitting bidirectional flow and introducing bonds of varying properties within the capillary network.</p><p>This system will allow us to investigate whether the wetting state of liquids in the network depends on its actuation history—essentially exploring whether capillary networks can exhibit memory. This question opens up new possibilities, including the potential to encode information within these networks, analyze how transport responds to external stimuli, study the interplay between global actuation and local fluid dynamics, explore the coupling between mechanics and flow, and better understand how information propagates through capillary systems.</p>
