In our body, a large number of molecules work cooperatively. As the result of the cooperation, molecules show special functions that the molecule cannot realize by alone. The aim of our research is fully-artificial creation of such a “fascinating function” due to nonlinear networks in multi-molecular systems, in vitro. This novel research field is known as Systems Chemistry.
The world leading achievement is an autonomous flapper shown in Figure 1. Generally, to make the repetitive motion of light-responsive materials, switching of light is required. However, the azobenzene crystals in the figure self-continue the periodical flipping under steady light irradiation. The mechanism for the self-sustainable motion is shown in Figure 2. In the original phase of the crystal, the forward reaction (trans-to-cis photoisomerization) occurs, and the increasing in the cis-isomer ratio induces a subcritical phase transition to a metastable crystal phase. In the newly formed crystal, cis-to-trans photoisomerization occurs, and the decrease in the cis-isomer ratio induces the reverse phase transition to the original crystal phase. Repeating the dynamics, the crystal shows mechanical flips repetitively to propel in water. Hokkaido University press-released the result with the title of “On the path toward molecular robots”. The news was translated into more than ten languages by publishers. You may watch the movie of clione-like motion of crystal from Hokudai’s YouTube (Figure 3).
The field of the research group is in multidiscipline area. All who interested in the research is welcomed to join.