News
Assistant Prof. Sugahara joined in the Energy and Photochemical Engineering Gr. (Prof. Hirai and Associate Prof. Shiraishi Gr.) from April 2020.

We have been studying so-called molecular clusters in the liquid solutions by use of scanning electron microscopy developed as "plasma replica SEM method", which combines SEM observation with the freeze-fracture replica method. The molecular cluster plays an important role of initiator of phase transition such as liquid-to-solid and gas-to-liquid. We are trying to control the function of molecular cluster in the microemulsion as an extremely small reaction space. SEM photograph shows BaSO4 nano-wire generated in the micro-emulsion. This technique is effective to produce a new functional material for our research purpose. Recently, to control supercooling of a phase change material (PCM), we are focusing on the solution structure of a supercooled aqueous solution.

BaSO4 nano-wire generated in the micro-emulsion

Fundamental Study on Gas Hydrate Crystal

Gas hydrates, which are regarded as key components in the provision for global warming problems, are one kind of inclusion components consisting of the guest molecules and hydrogen-bonded water cages. The unit lattice cell of the structure-I gas hydrate crystal is composed of two S-cages (pentagonal dodecahedron) and six M-cages (tetra-kaidecahedron having two opposite hexagonal faces and twelve pentagonal faces). We have been studying fundamental properties of gas hydrates such as thermodynamic stability, hydrate-cage occupancy by pressurization, hydrate-cage selectivity in the binary guest species and so.

unit cell of structure-I

Application of Gas Hydrates to Global Environmental Problems

Gas hydrates have recently attracted many investigators' attention as key components with a counter-plan for global green-house feed back problem. Also natural-gas hydrate fields having a large amount of methane deposits have become the object of public attention as a potential natural-gas resource. We have proposed an idea of methane exploitation in linkage with carbon dioxide isolation. The methane molecule in the hydrate-cage is pushed out by the carbon dioxide molecule, and then the carbon dioxide is finally trapped in the hydrate-cage. We have also been studying carbon dioxide storage process under the deep ocean, natural-gas transport system using gas hydrate pellets, high-pressure separation of hydrogen from gas-mixtures containing carbon dioxide, hydrogen storage using gas hydrates, and temperature preservation using hydrate formation and dissociation.

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