Mimicking the Natural World with Nanoarchitectonics for Self-Assembled Superstructures

Layer-by-Layer Nanoarchitectonics: A Method for Everything in Layered Structures

The development of functional materials and the use of nanotechnology are ongoing projects. These fields are closely linked, but there is a need to combine them more actively. Nanoarchitectonics, a concept that comes after nanotechnology, is ready to do this. Among the related research efforts, research into creating functional materials through the formation of thin layers on surfaces, molecular membranes, and multilayer structures of these materials have a lot of implications. Layered structures are especially important as a key part of nanoarchitectonics. The diversity of the components and materials used in layer-by-layer (LbL) assemblies is a notable feature. Examples of LbL assemblies introduced in this review article include quantum dots, nanoparticles, nanocrystals, nanowires, nanotubes, g-C3N4, graphene oxide, MXene, nanosheets, zeolites, nanoporous materials, sol-gel materials, layered double hydroxides, metal-organic frameworks, covalent organic frameworks, conducting polymers, dyes, DNAs, polysaccharides, nanocelluloses, peptides, proteins, lipid bilayers, photosystems, viruses, living cells, and tissues. These examples of LbL assembly show how useful and versatile it is. Finally, this review will consider future challenges in layer-by-layer nanoarchitectonics.

Materials Nanoarchitectonics for Advanced Devices

Advances in nanotechnology have made it possible to observe and evaluate structures down to the atomic and molecular level. The next step in the development of functional materials is to apply the knowledge of nanotechnology to materials sciences. This is the role of nanoarchitectonics, which is a concept of post-nanotechnology. Nanoarchitectonics is defined as a methodology to create functional materials using nanounits such as atoms, molecules, and nanomaterials as building blocks. Nanoarchitectonics is very general and is not limited to materials or applications, and thus nanoarchitecture is applied in many fields. In particular, in the evolution from nanotechnology to nanoarchitecture, it is useful to consider the contribution of nanoarchitecture in device applications. There may be a solution to the widely recognized problem of integrating top-down and bottom-up approaches in the design of functional systems. With this in mind, this review discusses examples of nanoarchitectonics in developments of advanced devices. Some recent examples are introduced through broadly dividing them into organic molecular nanoarchitectonics and inorganic materials nanoarchitectonics. Examples of organic molecular nanoarchitecture include a variety of control structural elements, such as π-conjugated structures, chemical structures of complex ligands, steric hindrance effects, molecular stacking, isomerization and color changes due to external stimuli, selective control of redox reactions, and doping control of organic semiconductors by electron transfer reactions. Supramolecular chemical processes such as association and intercalation of organic molecules are also important in controlling device properties. The nanoarchitectonics of inorganic materials often allows for control of size, dimension, and shape, and their associated physical properties can also be controlled. In addition, there are specific groups of materials that are suitable for practical use, such as nanoparticles and graphene. Therefore, nanoarchitecture of inorganic materials also has a more practical aspect. Based on these aspects, this review finally considers the future of materials nanoarchitectonics for further advanced devices.

Self-Assembly of Chemically Programmed Amphiphiles into Aqueous Nanotubes with a Lipophilic Lumen

The creation of complex hollow nanostructures with precise control over size and shape represents a great challenge in supramolecular soft materials. Here, we have further developed a bioinspired methodology for the formation of aqueous nanotubes of well-defined dimensions and pore coating through the self-assembly of amphiphiles that are chemically programmed with complementary nucleobases. These nanotubes are endowed with a hydrophobic lumen, whose diameter can be expanded as a function of the monomer length, in which apolar dyes can be efficiently encapsulated.

Liquid-Liquid and Liquid-Solid Interfacial Nanoarchitectonics

Nanoscale science is becoming increasingly important and prominent, and further development will necessitate integration with other material chemistries. In other words, it involves the construction of a methodology to build up materials based on nanoscale knowledge. This is also the beginning of the concept of post-nanotechnology. This role belongs to nanoarchitectonics, which has been rapidly developing in recent years. However, the scope of application of nanoarchitectonics is wide, and it is somewhat difficult to compile everything. Therefore, this review article will introduce the concepts of liquid and interface, which are the keywords for the organization of functional material systems in biological systems. The target interfaces are liquid-liquid interface, liquid-solid interface, and so on. Recent examples are summarized under the categories of molecular assembly, metal-organic framework and covalent organic framework, and living cell. In addition, the latest research on the liquid interfacial nanoarchitectonics of organic semiconductor film is also discussed. The final conclusive section summarizes these features and discusses the necessary components for the development of liquid interfacial nanoarchitectonics.

Self-assembled π-conjugated chromophores: preparation of one- and two-dimensional nanostructures and their use in photocatalysis

Photocatalytic systems have attracted research interest as a clean approach to generate energy from abundant sunlight. In this context, developing efficient and robust photocatalytic structures is crucial. Recently, self-assembled organic chromophores have entered the stage as alternatives to both molecular systems and (in)organic semiconductors. Nanostructures made of self-assembled π-conjugated dyes offer, on the one hand, molecular customizability to tune their optoelectronic properties and activities and on the other hand, provide benefits from heterogeneous catalysis that include ease of separation, recyclability and improved photophysical properties. In this contribution, we present recent achievements in constructing supramolecular photocatalytic systems made of chromophores for applications in water splitting, H2O2 evolution, CO2 reduction, or environmental remediation. We discuss strategies that can be used to prepare ordered photocatalytic systems with an emphasis on the effect of packing between the dyes and the resulting photocatalytic activity. We further showcase supramolecular strategies that allow interfacing the organic nanostructures with co-catalysts, molecules, polymers, and (in)organic materials. The principles discussed here are the foundation for the utilization of these self-assembled materials in photocatalysis.

Confined Space Nanoarchitectonics for Dynamic Functions and Molecular Machines

Nanotechnology has advanced the techniques for elucidating phenomena at the atomic, molecular, and nano-level. As a post nanotechnology concept, nanoarchitectonics has emerged to create functional materials from unit structures. Consider the material function when nanoarchitectonics enables the design of materials whose internal structure is controlled at the nanometer level. Material function is determined by two elements. These are the functional unit that forms the core of the function and the environment (matrix) that surrounds it. This review paper discusses the nanoarchitectonics of confined space, which is a field for controlling functional materials and molecular machines. The first few sections introduce some of the various dynamic functions in confined spaces, considering molecular space, materials space, and biospace. In the latter two sections, examples of research on the behavior of molecular machines, such as molecular motors, in confined spaces are discussed. In particular, surface space and internal nanospace are taken up as typical examples of confined space. What these examples show is that not only the central functional unit, but also the surrounding spatial configuration is necessary for higher functional expression. Nanoarchitectonics will play important roles in the architecture of such a total system.

Biomass Nanoarchitectonics for Supercapacitor Applications

Nanoarchitectonics integrates nanotechnology with numerous scientific disciplines to create innovative and novel functional materials from nano-units (atoms, molecules, and nanomaterials). The objective of nanoarchitectonics concept is to develop functional materials and systems with rationally architected functional units. This paper explores the progress and potential of this field using biomass nanoarchitectonics for supercapacitor applications as examples of energetic materials and devices. Strategic design of nanoporous carbons that exhibit ultra-high surface area and hierarchically pore architectures comprising micro- and mesopore structure and controlled pore size distributions are of great significance in energy-related applications, including in high-performance supercapacitors, lithium-ion batteries, and fuel cells. Agricultural wastes or natural biomass are lignocellulosic materials and are excellent carbon sources for the preparation of hierarchically porous carbons with an ultra-high surface area that are attractive materials in high-performance supercapacitor applications due to high electrical and ion conduction, extreme porosity, and exceptional chemical and thermal stability. In this review, we will focus on the latest advancements in the fabrication of hierarchical porous carbon materials from different biomass by chemical activation method. Particularly, the importance of biomass-derived ultra-high surface area porous carbons, hierarchical architectures with interconnected pores in high-energy storage, and high-performance supercapacitors applications will be discussed. Finally, the current challenges and outlook for the further improvement of carbon materials derived from biomass or agricultural wastes in the advancements of supercapacitor devices will be discussed.