Forceless spontaneous delamination of high-aspect ratio fluorohectorite into monolayer nanosheets in chloroform.

One-dimensional dissolution of a layered compound in a nonpolar organic solvent is reported for the first time. A high-aspect ratio fluorohectorite modified with a cationic surfactant (dioctadecyldimethylammonium) showed spontaneous delamination into monolayer nanosheets in chloroform.

Highly Luminescent Inorganic-Organic Hybrids with Molecularly Dispersed Perylene.

A highly photoluminescent material was obtained by the incorporation of perylene into an inorganic-organic hybrid film. Octosilicate, a layered alkali silicate, was modified with a cationic surfactant, dioleyldimethylammonium ion, to accommodate perylene molecularly and uniformly. The perylene-doped dioleyldimethylammonium octosilicate films were fabricated by simply casting the toluene solution of perylene with dispersed dioleyldimethylammonium octosilicate on substrates. Near-unity photoluminescence quantum efficiency was achieved for hybrids containing a high concentration of perylene.

Efficient Negative Photochromism by the Photoinduced Migration of Photochromic Merocyanine/Spiropyran in the Solid State.

Efficient negative photochromism was achieved by the photoinduced migration of merocyanine in mesoporous silica to an organophilic clay as spiropyran. Depending on the nature of the organophilic clays (dioctadecyldimethylammonium and dioleyldimethylammonium clays), important differences in the negative photochromisms and the thermal coloration were observed; the dioleyldimethylammonium clay gave a higher yield (98%) and faster reaction (half-life t1/2 = 2.8 h) than the dioctadecyldimethylammonium clay (94% and t1/2 = 3.2 h) of the negative photochromism, indicating the important role of the surfactant assembly to control the molecular diffusion.

Designing nanoarchitecture for environmental remediation based on the clay minerals as building block.

Nanoarchitecture of hybrids materials based on clay minerals as nano building blocks for the environmental remediation is summarized with the emphasis on the utilization of layered clay minerals, especially smectite group of clay minerals, as nano building blocks for designing functional nanostructures for the adsorption of molecular contaminants from the environments. Smectites are well-known adsorbents of cationic contaminants, while surface modification of smectites with organoammonium ions has given hydrophobic and microporous characters to uptake nonionic organic contaminants from environments. Not only on the designed interactions between adsorbent-adsorbate for efficient and higher capacity adsorption, the states of the adsorbed nonionic organic compounds have been altered and varied by the modification of smectites as shown by the controlled release and specific catalytic reactions. The organically modified clays are classified from the nanoarchitecture, and the functions derived from the nanoarchitectures are discussed based on the structure-property relationship.

Organically Modified Bentonite as an Efficient and Reusable Adsorbent for Triclosan Removal from Water.

Triclosan, an antibacterial agent, in the environment is of great concern; thus, an efficient method for its removal from an aqueous system is required. Removal of triclosan from water was achieved by an organically modified bentonite, dioctadecyldimethylammonium bentonite. The highest adsorbed amount achieved under the optimized conditions was 1750 mg·g-1, which is higher than that reported using such adsorbents as activated carbons, carbon nanotubes, zeolites, and other nanoporous materials. Complete removal of triclosan was achieved from the aqueous triclosan solution at a concentration 10 mg·L-1 using 3 mg/60 mL of 2C18-BT. The adsorbent was reusable, as examined by washing and reuse of the adsorbent for 5 cycles.

Novel Flexible Supramolecular Assembly of Dioleyldimethylammonium Ion in a Two-Dimensional Nanospace Studied by Neutron Scattering.

Dioleyldimethylammonium ion was used to construct two-dimensional hybrid structures with clay and the hybrid was shown to possess higher flexibility than that of the hybrid of dioctadecyldimethylammonium and the clay. The important difference between the two surfactant systems was studied by quasi-elastic neutron scattering, confirming the useful characteristics of the presently designed dioleyldimethylammonium-clay over the well-known dioctadecyldimethylammonium-clay for various materials applications.

Mechanochemical methods for the preparation of intercalation compounds, from intercalation to the formation of layered double hydroxides.

Due to increasing interest in the development of advanced nanomaterials from nanosheets as building blocks, methods for the preparation of nanosheet materials and their hybrids have been studied carefully and extensively. In this review, studies of mechanochemical methods (solid-solid reactions under ambient conditions or solvent-free synthesis) for the preparation of intercalation compounds are summarized. Mechanochemical reactions without using solvent have operational advantages, such as their environmentally benign nature and the fact that separating and drying the products is not necessary. In addition to their advantages from green chemistry viewpoints, solid-state reactions have potential for the preparation of novel intercalation compounds which are not accessible by conventional solution-based methods.