Unconventional soft-templating strategies for mesoporous metal oxides: beyond evaporation-induced self-assembly and calcination-based conversion

Abstract

Soft-templating methods based on block copolymer (BCP) self-assembly with inorganic precursors have been extensively used to synthesize a wide range of mesoporous metal oxides (MMOs). Among the various soft-templating approaches, evaporation-induced self-assembly (EISA) has emerged as the dominant platform. In a typical EISA process, mesostructured organic–inorganic composites are synthesized through BCP–precursor coassembly, followed by high-temperature treatment for conversion to MMOs. Despite the wide range of reported approaches, most EISA-based methods strongly rely on solvent evaporation for self-assembly and high-temperature processing for conversion to MMOs, which has created multiple process-related challenges. In this study, we highlight recently reported unconventional methods that address challenges stemming from both the self-assembly and conversion stages, with particular emphasis on self-assembly approaches that do not rely on solvent evaporation and conversion approaches that enable mesostructure formation at substantially reduced temperatures. Furthermore, this study reviews emerging synthesis concepts and outlines future directions for increasing the applicability of soft-templating methods across diverse material systems. Soft-templating methods based on block copolymer self-assembly have been widely used to synthesize mesoporous metal oxides (MMOs). However, conventional evaporation-induced self-assembly (EISA) relies on toxic volatile solvents and high-temperature calcination, limiting process sustainability and substrate compatibility. This review highlights unconventional soft-templating strategies that overcome these challenges. For the self-assembly stage, mechanochemical and condensation-induced self-assembly approaches are discussed as alternatives to solvent evaporation. For the conversion stage, solvent extraction, microwave-assisted methods, and thermal activation–plasma synergy are examined. These emerging strategies offer greener, lower-temperature, and more versatile pathways toward functional MMOs.