Liquid Metal Soft Machines by Jing Liu & Lei Sheng & Zhi-Zhu He

Author:Jing Liu & Lei Sheng & Zhi-Zhu He
Language: eng
Format: epub
ISBN: 9789811327094
Publisher: Springer Singapore

8.5 Dynamic Motion of Al–Ga–In Alloy Droplet Motors

After the alloy was injected into NaOH solution, large amounts of liquid metal motors were immediately generated and dispersed in the Petri dish. After a few while, each small Al–Ga–In droplet began to move swiftly [2], just like a tiny motor in a seemingly random direction with H2 produced constantly at the bottom of the droplet. By quantifying the subsequent videos, it was found that the motion direction and velocity of the droplets frequently changed with the time. The collision happened inevitably because of the large droplet density. Some of the droplets may become coalesced after collision, some just bounced apart while some new small droplets were pinched off. This dynamic coalescence phenomenon is somewhat similar to the former case as observed on the gently contacting liquid metal droplets [17].

According to the experiments, the motion trajectory of any droplets in free space was overall unpredictable [2]. Considering that the majority of the tiny motors have reached the diameter of around 1 mm, which implied their macroscopic activities, the present work thus focused on the bulk motion behaviors of motors at this size. Such a phenomenon was termed as macroscopic Brownian like motion [2], although its mechanism is completely different from the classical one. The location of several droplets with different sizes along time can be recorded using a high-speed camera. Through processing the dynamic images, one can obtain the transient locations of six randomly picked droplets every 30 ms for a total 6 s. Assuming that the displacement during each time interval was linear, then the transient velocity at each location can be calculated. The motion trajectories and transient velocity probability distribution of six droplets with similar diameter during 6 s were depicted in Fig. 8.7, respectively. Overall, these results could typically reflect the motion characteristics. For motors with sizes much larger or smaller than the average ones, their speed was somewhat a little bit smaller. However, since such motors amount was very small, they were not taken into account as the samples.

Fig. 8.7Dynamic motion of six Al–Ga–In alloy droplets during 6 s [2]. The diameters of droplet A, B, C, D, E, F were 1.2 mm, 1.1 mm,1.2 mm, 1.0 mm, 1.0 mm, and 0.9 mm, respectively. a The transient trajectories of six droplets on the two-dimensional free surface of the glass Petri dish. b The probability distributions of transient velocities of each droplet.

All pictures are reproduced with permission

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.