Interfacial Assembly Directed Unique Mesoporous Architectures: From Symmetric to Asymmetric

Functional mesoporous materials have experienced flourishing developments over the past 30 years, and they are now a big family including large variety of compositions and architectures. Due to large surface area, high pore volume, tunable pore size, and unique mesostructures, mesoporous nanomaterials have been widely used in catalysis, energy conversion and storage, drug delivery, etc. Out of the various methods of architecting mesoporous materials, the soft-templating method that allows regulating the architecture by tuning the assembly process, is used mostly for fabricating mesoporous materials. In soft templating methods, amphiphilic surfactants and precursors assemble into soft micelles, and micelles further assemble into mesoporous materials. Usually, micelles homogeneously nucleate and assemble into mesoporous nanomaterials. Such a homogeneous assembly process naturally leads to routine structures such as nanospheres or other symmetric architectures. Introduction of nanoparticles during the micelle assembly process results in conventional core@shell structures, which though combining the mesoporous shell and functional core, is still simple. Nowadays, growing demands in diverse applications urgently require mesoporous nanomaterials with novelty in mesostructures, compositions, surface properties, morphologies, functionalities, etc. Therefore, researchers have been seeking to gain better control of the micelles' assembly process, pursuing the synthesis of mesoporous nanomaterials with unique architectures, especially morphology, mesostructure, surface chemistry, etc. Recently, the effect of interface during micelles' assembly process has aroused great attention. The introduction of an interface into the reaction system turns the micelles' homogeneous assembly into a heterogeneous one, altering their assembly behavior and thus leading to mesoporous nanomaterials with unique architectures. By manipulation of the interfacial-assembly behavior of micelles, a series of mesoporous nanomaterials with unique architectures have been developed, with structures ranging from symmetric to asymmetric. In this Account, the recent progresses in interfacial-assembly-directed mesoporous nanomaterials with unique architectures, both the fabrication and applications are systematic reviewed. The architectures of the obtained mesoporous nanomaterials are categorized into symmetric and asymmetric, including virus-like, bouquet-like, multishell hollow structures, and also Janus, multipods, hemisphere structures, etc. We introduced how interfaces such as nanoparticle-surface, water-oil interface, macropore scaffold interfaces, etc. are utilized to direct the assembly of micelles. The methods of controlling micelles' interfacial-assembly behavior, such as biphasic assembly method, interfacial-energy method, interface tension method, and so on are highlighted. The applications of these unique mesoporous nanomaterials in fields of catalysis, energy conversion, and biomedicine are surveyed. At the end of the review, a brief summary of the field, as well as shortcomings, challenges, and perspectives of the field are also included.