Publications OK SMART LAB

Nozzle-Free Liquid Microjetting via Homogeneous Bubble Nucleation
Authors
Taehwa Lee, Hyoung Won Baac, Jong G. Ok, Hong Seok Youn, and L. Jay Guo
Journal
Physical Review Applied
Vol. (No.), pp.
3 (4), 044007 (Apr 2015)
Year
2020-2014
We propose and demonstrate a physical mechanism for producing liquid microjets by taking an optoacoustic approach that can convert light to sound through a carbon-nanotube-coated lens, where light from a pulsed laser is converted to high momentum sound wave. The carbon-nanotube lens can focus high-amplitude sound waves to a microspot of <1⁢00  ????⁢m near the air-water interface from the water side, leading to microbubbles in water and subsequent microjets into the air. Laser-flash shadowgraphy visualizes two consecutive jets closely correlated with bubble dynamics. Because of the acoustic scattering from the interface, negative pressure amplitudes are significantly increased up to 80 MPa, even allowing homogeneous bubble nucleation. As a demonstration, this nozzle-free approach is applied to inject colored liquid into a tissue-mimicking gel as well as print a material on a glass substrate.