Skip to main content
Log in

Self-powered macroscopic Brownian motion of spontaneously running liquid metal motors

  • Article
  • Engineering Sciences
  • Published:
Science Bulletin


We disclosed the interiorly driven macroscopic Brownian motion behavior of self-powered liquid metal motors. Such tiny motors in millimeter scale move randomly at a velocity magnitude of centimeters per second in aqueous alkaline solution, well resembling the classical Brownian motion. However, unlike the existing phenomena, where the particle motions were caused by collisions from the surrounding molecules, the current random liquid metal motions are internally enabled and self-powered, along with the colliding among neighboring motors, the substrate and the surrounding electrolyte molecules. Through uniformly dissolving only 1 % (mass percentage) Al into GaIn10, many tiny motors can be quickly fabricated and activated to take the Brownian-like random motions. Further, we introduced an experimental approach of using optical image contrast, which works just like the Wilson cloud chamber, to distinctively indicate the motor trajectory resulted from the generated hydrogen gas stream. A series of unusual complicated multi-phase fluid mechanics phenomena were observed. It was also identified that the main driving factor of the motors comes from the H2 bubbles generated at the bottom of these tiny motors, which is different from the large size self-fueled liquid metal machine. Several typical mechanisms for such unconventional Brownian-like motion phenomena were preliminarily interpreted.


本文揭示了液态金属马达在碱性水溶液中类布朗运动的机制:固-液界面接触产氢。实验将微量铝箔(质量分数1%)融入GaIn10中,以注射方式产生大量自主运动型微小马达。采用高速摄像仪记录,并基于图像处理量化进行分析。结果表明液态金属马达呈现高速(约4 cm/s)无序的运动模式,我们将其命名为宏观布朗运动。不同于经典布朗现象,宏观布朗运动系由液态金属合金产氢反应、液态金属马达间及其与溶液和基底的多重相互作用所致。此外,通过搭建类似于威尔逊云室的光学平台可以清晰显示液态金属马达产生的氢气轨迹,并证实驱动马达的主要因素来自氢气泡,这与大尺寸液态金属机器主要受表面张力驱动的机制不同。

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others


  1. Sheng L, Zhang J, Liu J (2014) Diverse transformations of liquid metals between different morphologies. Adv Mater 26:6036–6042

    Article  Google Scholar 

  2. Tang SY, Khoshmanesh K, Sivan V et al (2014) Liquid metal enabled pump. Proc Natl Acad Sci USA 111:3304–3309

    Article  Google Scholar 

  3. Kim D, Lee JB (2015) Magnetic-field-induced liquid metal droplet manipulation. J Korean Phys Soc 66:282–286

    Article  Google Scholar 

  4. Tang X, Tang SY, Sivan V et al (2013) Photochemically induced motion of liquid metal marbles. Appl Phys Lett 103:174104

    Article  Google Scholar 

  5. Ma K, Liu J (2007) Liquid metal cooling in thermal management of computer chips. Front Energy Power Eng China 1:384–402

    Article  Google Scholar 

  6. Tang SY, Sivan V, Petersen P et al (2014) Liquid metal actuator for inducing chaotic advection. Adv Funct Mater 24:5851–5858

    Article  Google Scholar 

  7. Sánchez S, Soler L, Katuri J (2015) Chemically powered micro- and nanomotors. Angew Chem Int Ed 54:1414–1444

    Article  Google Scholar 

  8. Zhang J, Yao Y, Sheng L et al (2015) Self-fueled biomimetic liquid metal mollusk. Adv Mater 27:2648–2655

  9. Zhang J, Yao Y, Liu J (2015) Autonomous convergence and divergence of the self-powered soft liquid metal vehicles. Sci Bull 60:943–951

    Article  Google Scholar 

  10. Haw MD (2002) Colloidal suspensions, Brownian motion, molecular reality: a short history. J Phys Condens Matter 4:7769

    Article  Google Scholar 

  11. Einstein A (1956) Investigations on the theory of the Brownian movement. Dover Publications, INC

  12. Hänggi P, Marchesoni F (2005) 100 years of Brownian motion. arXiv: preprint cond-mat/0502053

  13. Gao W, Pei A, Wang J (2012) Water-driven micromotors. ACS Nano 6:8432–8438

    Article  Google Scholar 

  14. Yu Y, Wang Q, Yi L et al (2014) Channelless fabrication for large-scale preparation of room temperature liquid metal droplets. Adv Eng Mater 16:255–262

    Article  Google Scholar 

  15. Yuan B, He Z, Fang W et al (2015) Liquid metal spring: oscillating coalescence and ejection of contacting liquid metal droplets. Sci Bull 60:648–653

    Article  Google Scholar 

  16. Mazur P (1959) On the theory of Brownian motion. Physica 25:149–162

    Article  Google Scholar 

  17. Flamini DO, Saidman SB, Bessone JB (2006) Aluminium activation produced by gallium. Corros Sci 48:1413–1425

    Article  Google Scholar 

  18. Ziebarth JT, Woodall JM, Kramer RA et al (2011) Liquid phase-enabled reaction of Al–Ga and Al–Ga–In–Sn alloys with water. Int J Hydrogen Energy 36:5271–5279

    Article  Google Scholar 

  19. Happel J, Brenner H (1983) Low Reynolds number hydrodynamics: with special applications to particulate media (Vol. 1). Martinus NijHoff Publishers, The Hague

    Google Scholar 

  20. Aarts DGAL, Lekkerkerker HNW (2008) Droplet coalescence: drainage, film rupture and neck growth in ultralow interfacial tension systems. J Fluid Mech 606:275–294

    Article  Google Scholar 

  21. Stojek Z (2002) The electrical double layer and its structure. Electroanalytical methods. Springer, Berlin, pp 3–8

    Google Scholar 

  22. Gupta NND, Ghosh SK (1946) A report on the Wilson cloud chamber and its applications in physics. Rev Mod Phys 18:225–290

    Article  Google Scholar 

Download references


This work was supported by Research Funding of Chinese Academy of Sciences and partially by the National Natural Science Foundation of China (51376102).

Conflict of interest

The authors declare that they have no conflict of interest.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Jing Liu.

Additional information

Bin Yuan and Sicong Tan contributed equally to this work.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (MP4 3503 kb)

Supplementary material 2 (MP4 5684 kb)

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yuan, B., Tan, S., Zhou, Y. et al. Self-powered macroscopic Brownian motion of spontaneously running liquid metal motors. Sci. Bull. 60, 1203–1210 (2015).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: