Self-Propulsion of a Light-Powered Microscopic Crystalline Flapper in Water.

Kazuma Obara,Yoshiyuki Kageyama,Sadamu Takeda

doi:10.1002/smll.202105302

Kazuma Obara, Yoshiyuki Kageyama + Show 1 more

Open Access

https://doi.org/10.1002/smll.202105302

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Abstract

A key goal in developing molecular microrobots that mimic real-world animal dynamic behavior is to understand better the self-continuous progressive motion resulting from collective molecular transformation. This study reports, for the first time, the experimental realization of directional swimming of a microcrystal that exhibits self-continuous reciprocating motion in a 2D water tank. Although the reciprocal flip motion of the crystals is like that of a fish wagging its tail fin, many of the crystals swam in the opposite direction to which a fish would swim. Here the directionality generation mechanism and physical features of the swimming behavior is explored by constructing a mathematical model for the crystalline flapper. The results show that a tiny crystal with a less-deformable part in its flip fin exhibits a pull-type stroke swimming, while a crystal with a fin that uniformly deforms exhibits push-type kicking motion.

Highlights

The development of molecular microrobots with motional dynamics based on the characteristics of living systems has attracted considerable attention from physicists and chemists, and offers enormous potential in applications ranging from intelligent machines to biomedical devices.[1,2,3,4]
Characterization of crystal swimming styles The crystal showed self-continuous flipping under continuous irradiation by blue light through a sequence of time-irreversible processes, in which light-triggered isomerization of 1 (Steps 1 and 3, in Figure 2) induced a crystalline phase transition (Steps 2 and 4) which repeatedly progressed without external control
In terms of the model, stroke style swimming occurred when the rotation of panel-2 preceded that of panel-1

Summary

Introduction

The development of molecular microrobots with motional dynamics based on the characteristics of living systems has attracted considerable attention from physicists and chemists, and offers enormous potential in applications ranging from intelligent machines to biomedical devices.[1,2,3,4] The first challenge to overcome to enable progress toward these potential applications is attaining self-organized macroscopic dynamics in molecular machines. Development of the mathematical model we set a three-panels-two-torsion springs object with 100 μm length, 40 μm width, and 1 μm height as a model to simulate the curved bending of the molecular crystal (Figure 1).

Results

Conclusion