Self-Assembly of Hierarchical Macroporous Metal-Organic Framework Films Guided by Hydrophilic-Lipophilic Balance

Abstract

Metal–organic framework (MOF) films possess versatile chemical functionalities, intrinsic microporosity, and facile integration with surfaces and devices, generating significant interest across diverse fields. However, precise control over large-area MOF films with hierarchical micro- and macroporosity remains challenging because it is difficult to simultaneously maintain multiscale porosity, structural integrity, and film uniformity. In this study, we developed a hydrophilic–lipophilic balance (HLB)-guided strategy for the self-assembly of hierarchical macroporous UiO-66 (Ce) films with well-defined bimodal pore structures. Systematic tuning of the total HLB (HLBtotal) and surfactant architecture modulated the interfacial tension and mixed micelle behavior, yielding uniform hierarchical macroporous films at an HLBtotal of 11. Dissipative particle dynamics (DPD) simulations further showed that differences in HLB among surfactants affect micellar miscibility and interfacial stability, thereby influencing micelle organization and structural evolution during film growth. The resulting hierarchical macroporous UiO-66 (Ce) films exhibited enhanced catalytic performance in glycerol acetalization, attributed to improved mass transport and an increased number of active sites. This study provides fundamental insights into HLB-guided self-assembly of hierarchical macroporous MOF films, thereby contributing to the rational design of advanced porous materials for catalytic and separation applications.