Khattak, Hamza K.; Waitukaitis, Scott RIST Austria ; Slepkov, Aaron D.
When grape-sized aqueous dimers are irradiated in a microwave oven, an intense electromagnetic hotspot forms at their point of contact, often igniting a plasma. Here we show that this irradiation can result in the injection of mechanical energy. By examining irradiated hydrogel dimers through high-speed imaging, we find that they repeatedly bounce off of each other while irradiated. We determine that an average of 1 lJ of mechanical energy is injected into the pair during each collision. Furthermore, a characteristic high-pitched audio signal is found to accompany each collision. We show that both the audio signal and the energy injection arise via an interplay between vaporization and elastic deformations in the region of contact, the so-called ‘elastic Liedenfrost effect’. Our results establish a novel, non-contact method of injecting mechanical energy into soft matter systems, suggesting application in fields such as soft robotics.
Khattak HK, Waitukaitis SR, Slepkov AD. Microwave induced mechanical activation of hydrogel dimers. Soft Matter. 2019;15(29):5804-5809. doi:10.1039/c9sm00756c
Khattak, H. K., Waitukaitis, S. R., & Slepkov, A. D. (2019). Microwave induced mechanical activation of hydrogel dimers. Soft Matter, 15(29), 5804–5809. https://doi.org/10.1039/c9sm00756c
Khattak, Hamza K., Scott R Waitukaitis, and Aaron D. Slepkov. “Microwave Induced Mechanical Activation of Hydrogel Dimers.” Soft Matter 15, no. 29 (2019): 5804–9. https://doi.org/10.1039/c9sm00756c.
H. K. Khattak, S. R. Waitukaitis, and A. D. Slepkov, “Microwave induced mechanical activation of hydrogel dimers,” Soft Matter, vol. 15, no. 29, pp. 5804–5809, 2019.
Khattak HK, Waitukaitis SR, Slepkov AD. 2019. Microwave induced mechanical activation of hydrogel dimers. Soft Matter. 15(29), 5804–5809.
Khattak, Hamza K., et al. “Microwave Induced Mechanical Activation of Hydrogel Dimers.” Soft Matter, vol. 15, no. 29, Royal Society of Chemistry, 2019, pp. 5804–09, doi:10.1039/c9sm00756c.