Kawashima Hisato, Shioi Akihisa, Archer Richard J, Ebbens Stephen J, Nakamura Yoshinobu, Fujii Syuji
Division of Applied Chemistry, Graduate School of Engineering, Osaka Institute of Technology 5-16-1 Omiya, Asahi-ku Osaka 535-8585 Japan.
Department of Chemical Engineering and Materials Science, Doshisha University Kyoto 610-0321 Japan
RSC Adv. 2019 Mar 13;9(15):8333-8339. doi: 10.1039/c9ra01417a. eCollection 2019 Mar 12.
A centimeter-sized flat-headed push pin with photothermal properties can be moved on a water surface by a simple near-infrared laser. Using light as an external stimulus allows for the remote control of the timing, direction and velocity of its locomotion. It has been clarified that the vertical orientation of the pin at the air-water interface affects the friction of locomotion, and therefore velocity and acceleration. The pin placed on a water surface with a pin point upward (a point protruding into air phase) moved an average distance of 5.3 ± 2.9 cm following one pulse of laser irradiation, and that placed with a pin point downward (a point protruding into water phase) moved 2.0 ± 1.4 cm. The velocity and acceleration were larger when the pin was placed on the water surface with a pin pointing upward, compared to when placed with the pin pointing downward. Numerical analysis conducted for the locomotions of the pin concluded that the differences in traveling distance, velocity and acceleration were due to the difference in fluid resistance of the pin point in air and water phases during their locomotion. This demonstration of remote control of the motion of small objects by light can open up a wide range of future transport applications.
一种具有光热特性的厘米大小的平头图钉可以通过简单的近红外激光在水面上移动。利用光作为外部刺激可以远程控制其运动的时间、方向和速度。已经明确，图钉在气-水界面处的垂直方向会影响运动的摩擦力，进而影响速度和加速度。针尖向上（针尖突出到气相中）放置在水面上的图钉在一次激光照射脉冲后平均移动距离为5.3±2.9厘米，而针尖向下（针尖突出到水相中）放置的图钉移动了2.0±1.4厘米。与针尖向下放置相比，针尖向上放置在水面上时，图钉的速度和加速度更大。对图钉运动进行的数值分析得出结论，行进距离、速度和加速度的差异是由于图钉在空气中和水中运动时针尖处流体阻力的差异所致。这种通过光对小物体运动进行远程控制的演示可以为未来广泛的运输应用开辟道路。
