26 Interplay of Photoisomerization and Phase Transition Events …
459
trigger a phase transition of the crystal, and then it accepts feedback in the manner
described above. Meanwhile, the other molecules serve as building blocks to prevent
the assembly from breaking down. Our most recent results further indicate that the
latter molecules also play a role in selecting the path for the periodic cycle of this
system. As a result, periodic changes in shape are varied according to the externally
defined light-polarity.
26.5 Conclusion and Remarks Regarding Self-Organized
Molecular Motors
The inventions of the water mill and windmill have proved very important for
advances in agriculture. Meanwhile, the invention of the steam engine has allowed
humans to move objects as small as electrons to objects as large as ships. The key
to all of these inventions is that the objects involved are connected to motors. There
is no exception. Thus, when we create a self-moving microrobot, we must have a
suitable motor.
To date, organic chemists have synthesized molecules that undergo salient changes
in their structures. If a cyclic change occurs when steady energy supply is available,
this has been considered a molecular motor according to traditional definition. On
the other hand, if the change in structure requires alterations in the conditions of
the molecule to achieve the change in structure, this has been considered a molecular machine. In parallel, material scientists have worked on generating microrobots
which move under the direction of remote control. In these microrobots, molecular machine has been employed rather than molecular motors [68, 69], because an
unsynchronized molecular motor is never worked. However, to attain an autonomous
function in microrobot, a suitable molecular motor system is needed.
To date, our ability to obtain work from a molecular motor remains insufficient.
One reason may be that we need to better understand molecular self-organization.
A series of theoretical studies related to dissipative structures have clearly indicated
how autonomous energy conversion can occur in a mesoscale molecular system.
A dissipative structure involves a dynamic whereby multiple nonlinear processes
are coupled in a feedback manner. As a result, they form a spatial and temporal
system which exhibits self-continuous dynamics compared with the original process
shown in Figs. 26.2 and 26.7. The importance of dissipative structures is their farfrom-equilibrium behavior: the distance from so-called equilibrium (not thermal
equilibrium) is related to the capability of the mechanical function which a system
can accomplish. Moreover, this distance from equilibrium is required to be maintained despite the generation of external disturbances as the system acts on external
objects. Therefore, the limit-cycle-type self-oscillation system described in this
chapter appears to be the best system for developing a motorization system [70].
459
trigger a phase transition of the crystal, and then it accepts feedback in the manner
described above. Meanwhile, the other molecules serve as building blocks to prevent
the assembly from breaking down. Our most recent results further indicate that the
latter molecules also play a role in selecting the path for the periodic cycle of this
system. As a result, periodic changes in shape are varied according to the externally
defined light-polarity.
26.5 Conclusion and Remarks Regarding Self-Organized
Molecular Motors
The inventions of the water mill and windmill have proved very important for
advances in agriculture. Meanwhile, the invention of the steam engine has allowed
humans to move objects as small as electrons to objects as large as ships. The key
to all of these inventions is that the objects involved are connected to motors. There
is no exception. Thus, when we create a self-moving microrobot, we must have a
suitable motor.
To date, organic chemists have synthesized molecules that undergo salient changes
in their structures. If a cyclic change occurs when steady energy supply is available,
this has been considered a molecular motor according to traditional definition. On
the other hand, if the change in structure requires alterations in the conditions of
the molecule to achieve the change in structure, this has been considered a molecular machine. In parallel, material scientists have worked on generating microrobots
which move under the direction of remote control. In these microrobots, molecular machine has been employed rather than molecular motors [68, 69], because an
unsynchronized molecular motor is never worked. However, to attain an autonomous
function in microrobot, a suitable molecular motor system is needed.
To date, our ability to obtain work from a molecular motor remains insufficient.
One reason may be that we need to better understand molecular self-organization.
A series of theoretical studies related to dissipative structures have clearly indicated
how autonomous energy conversion can occur in a mesoscale molecular system.
A dissipative structure involves a dynamic whereby multiple nonlinear processes
are coupled in a feedback manner. As a result, they form a spatial and temporal
system which exhibits self-continuous dynamics compared with the original process
shown in Figs. 26.2 and 26.7. The importance of dissipative structures is their farfrom-equilibrium behavior: the distance from so-called equilibrium (not thermal
equilibrium) is related to the capability of the mechanical function which a system
can accomplish. Moreover, this distance from equilibrium is required to be maintained despite the generation of external disturbances as the system acts on external
objects. Therefore, the limit-cycle-type self-oscillation system described in this
chapter appears to be the best system for developing a motorization system [70].