Salvinia-inspired architectures for enhancing interface stability and mass transfer in microchannels.

Abstract

Mass transfer in conventional microchannels primarily relies on wall-mediated diffusion or is compromised by dynamic instability at free interfaces, which limits interphase transport efficiency. Inspired by the hierarchical trichomes of Salvinia molesta leaves, we designed composite architectures featuring spatially selective hydrophilic modification via in situ polydopamine (PDA) grafting, which enhance mass transfer while maintaining interface stability in microchannels. High-speed imaging was used to capture the dynamic evolution of interfacial morphology, revealing failure behaviours consistent with theoretical analysis. Cyclic pressure loading experiments confirmed that the modified architecture exhibited strong interfacial pinning, increasing the stable operating pressure range by over 20% and doubling the tolerable disturbance frequency. By establishing mass transfer models, we demonstrated that this robust stability enabled efficient gas-liquid mass transfer and verified its potential for liquid-liquid extraction applications, especially under dynamic pulsatile flow conditions, where the mass transfer efficiency was improved by more than 15% compared to static conditions. This work presents an interfacial engineering strategy that combines structural design with surface wettability control, with broad potential in biological and chemical separation, gas-liquid reactions, and multiphase microfluidics.