Machine Learning-Guided Design of ZIF-8 Polymer Nanocomposites for Sustainable Applications: Current Progress and Future Opportunities

The integration of zeolitic imidazolate framework-8 (ZIF-8) into polymer matrices has created a versatile class of nanocomposites with potential applications in gas separation, water purification, food packaging, sensing, catalysis, energy systems, and environmental remediation. However, their performance is governed by complex and strongly coupled variables, including ZIF-8 particle size, morphology, defect density, surface chemistry, filler loading, polymer compatibility, interfacial adhesion, dispersion state, and processing conditions. To organize this complexity, the review introduces a hierarchical design framework that distinguishes controllable synthesis and processing inputs, experimentally measurable intermediate material states, and condition-dependent performance outputs, thereby providing a structured basis for machine-learning-ready data representation. Conventional trial-and-error approaches are therefore often inefficient and provide limited capacity to identify transferable structure–processing–property relationships. This review examines the emerging role of machine learning (ML) in the rational design and optimization of ZIF-8/polymer nanocomposites for sustainable applications. Particular attention is given to the construction of material descriptors, selection of predictive algorithms, interpretation of feature importance, optimization of synthesis and processing parameters, and prediction of mechanical, thermal, barrier, transport, adsorption, catalytic, and antimicrobial properties. The review further discusses how supervised learning, explainable artificial intelligence, active learning, Bayesian optimization, transfer learning, and physics-informed models can support material screening and multi-objective optimization across performance, cost, energy consumption, environmental impact, and end-of-life considerations. Current limitations, including small and heterogeneous datasets, inconsistent reporting, insufficient negative results, limited model interpretability, and weak experimental validation, are critically evaluated. A future framework is proposed that integrates standardized databases, high-throughput experimentation, multiscale characterization, life-cycle indicators, uncertainty quantification, and closed-loop machine learning. Such an approach could accelerate the transition from empirical formulation toward data-driven, interpretable, and sustainability-oriented design of ZIF-8/polymer nanocomposites.