Controlling MOF adsorbent fiber morphology via wet spinning: rheology and dimensionless parameter effects

Metal-organic framework (MOF)-based adsorbent fibers present a transformative opportunity for CO₂ capture systems, combining high surface area with engineered flow characteristics. Wet spinning of MOF suspensions enables scalable fabrication of these functional fibers, where precise control over fiber diameter and porosity is critical for optimizing adsorption kinetics and mechanical durability. However, achieving uniform fiber morphology remains challenging due to complex particle-fluid interactions during spinning. We demonstrate controlled fabrication of MOF-based adsorbent fibers for CO₂ capture through wet spinning of composite suspensions containing MOFs, polyethyleneimine (PEI), and carbon black (CB). By characterizing suspension rheology and systematically varying process parameters, we establish how the Weber (We) and Capillary (Ca) numbers govern fiber characteristics (diameter, surface roughness, MOF distribution). Our approach decouples fluid-driven morphology control from material-specific interactions, enabling controlled diameter tuning at constant MOF loading and preserves MOF crystallinity and adsorption capacity. This framework provides a generalized strategy for manufacturing tailored adsorbent fibers, advancing the integration of advanced materials with scalable fluid processing for gas separation technologies.