The layer-by-layer (LbL) adsorption technique offers an easy and inexpensive process for multilayer formation and allows a variety of materials to be incorporated within the film structures. Therefore, the LbL assembly method can be regarded as a versatile bottom-up nanofabrication technique. Research fields concerned with LbL assembly have developed rapidly but some important physicochemical aspects remain uninvestigated. In this review, we will introduce several examples from physicochemical investigations regarding the basics of this method to advanced research aimed at practical applications. These are selected mostly from recent reports and should stimulate many physical chemists and chemical physicists in the further development of LbL assembly. In order to further understand the mechanism of the LbL assembly process, theoretical work, including thermodynamics calculations, has been conducted. Additionally, the use of molecular dynamics simulation has been proposed. Recently, many kinds of physicochemical molecular interactions, including hydrogen bonding, charge transfer interactions, and stereo-complex formation, have been used. The combination of the LbL method with other fabrication techniques such as spin-coating, spraying, and photolithography has also been extensively researched. These improvements have enabled preparation of LbL films composed of various materials contained in well-designed nanostructures. The resulting structures can be used to investigate basic physicochemical phenomena where relative distances between interacting groups is of great importance. Similarly, LbL structures prepared by such advanced techniques are used widely for development of functional systems for physical applications from photovoltaic devices and field effect transistors to biochemical applications including nano-sized reactors and drug delivery systems.

An amphiphilic hexa- peri -hexabenzocoronene self-assembles to form a π-electronic, discrete nanotubular object. The object is characterized by an aspect ratio greater than 1000 and has a uniform, 14-nanometer-wide, open-ended hollow space, which is an order of magnitude larger than those of carbon nanotubes. The wall is 3 nanometers thick and consists of helical arrays of the π-stacked graphene molecule, whose exterior and interior surfaces are covered by hydrophilic triethylene glycol chains. The graphitic nanotube is redox active, and a single piece of the nanotube across 180-nanometer-gap electrodes shows, upon oxidation, an electrical conductivity of 2.5 megohms at 285 kelvin. This family of molecularly engineered graphite with a one-dimensional tubular shape and a chemically accessible surface constitutes an important step toward molecular electronics.

Materials fabrication with nanoscale structural precision based on bottom-up-type self-assembly has become more important in various current disciplines in chemistry including materials chemistry, organic chemistry, physical chemistry, analytical chemistry, biochemistry, colloid and surface chemistry, and supramolecular chemistry. Although the design of new materials based on nanoscale self-assembly is anticipated as a key concept, preparing complete three-dimensional structures at nanoscale precision remains a difficult target using current technologies. Rather, dimension-reduced approaches such as layering of two-dimensional nanostructures into precisely controlled lamellar nanomaterials are currently achievable. In particular, layer-by-layer (LbL) assembly is known as a highly versatile method for fabrication of controlled layered structures from various kinds of component materials using very simple, inexpensive, and rapid procedures. Therefore, fabrication of multilayer films through the LbL deposition process has attracted growing interest from various research communities. The high versatility and flexibility of LbL assembly is continuously creating new concepts, new materials, new procedures, and new applications. In this highlight review, we focus on nanoarchitectonics by LbL assembly. After an initial introduction on the invention and a brief history of the LbL assembly technique, innovations and the evolution of the technique are described based mainly on recent examples, which are categorized into two sections: (i) developments in methodology (technical, material, and phenomenological aspects with expansion of concept) and (ii) progress in applications (physical, chemical/biochemical, and biomedical applications).

The controlled fabrication of nanometer-scale objects is without doubt one of the central issues in current science and technology. However, existing fabrication techniques suffer from several disadvantages including size-restrictions and a general paucity of applicable materials. Because of this, the development of alternative approaches based on supramolecular self-assembly processes is anticipated as a breakthrough methodology. This review article aims to comprehensively summarize the salient aspects of self-assembly through the introduction of the recent challenges and breakthroughs in three categories: (i) types of self-assembly in bulk media; (ii) types of components for self-assembly in bulk media; and (iii) self-assembly at interfaces.

Although mesoporous materials have well-defined pore structures, these fine materials can surprisingly be produced by employing a set of conventional and simple procedures such as mixing, heating, filtration, and washing, using low-cost materials. They can be regarded as easy-to-make bulk nanostructured materials. Mesoporous materials have great potential for use in both macroscopic applications and nanotechnology. In this account, we introduce examples of recent developments in mesoporous materials involving innovations in their components and structural designs and concentrating on our own recent progress. These examples include syntheses of mesoporous silica, metal oxides, semiconductive materials, metals, alloys, organic composites, biomaterial composites, carbon, carbon nitride, and boron nitride, as innovative components. As structural innovations for mesoporous materials, various film preparations, pore alignments, and hierarchic structures are described together with their related functions including sensing and controlled release of target molecules.