Ultrasonic near-field based acoustic tweezers for the extraction and manipulation of hydrocarbon droplets

Radiation pressure from acoustic and electromagnetic fields can generate forces sufficient to trap and manipulate objects. In most cases, the objects are pre-existing, but it is also possible for the forces to essentially create the target objects. Recently, we reported on the ability of high power ultrasound to extract and controllably manipulate droplets from the organic solvent CCl4 using a near-field type of acoustic tweezers [Lirette et al., Phys. Rev. Appl. 12, 061001 (2019)]. The extraction used a fraxicon lens which produced trapping zones in the near-field. With the addition of extraction to trapping and manipulation, the process can be considered a form of contact-free pipetting. In the present work, we demonstrate the capability of this system to co-axially extract two droplets of SAE30ND motor oil (between 70%–80% liquid hydrocarbon) at a water interface against a positive radiation pressure. In the experiments with oil, several differences in the process have been observed relative to the CCl4 study: a second near-field trapping zone is revealed; the surface deformation is small and opposite to the direction of extraction; the extraction and trapping forces are sufficient to overcome both interfacial tension and buoyancy; and the target liquid has distinct physical properties, such as density, viscosity, and acoustic impedance. Non-contact and label-free extraction of oil droplets remotely in an aqueous environment could have significant biological and environmental applications. Finding that the process works with two distinct liquids demonstrates its more general applicability and broadens its potential uses.

[1]  Qian Shi,et al.  Acoustic focusing of beads and cells in hydrogel droplets , 2021, Scientific Reports.

[2]  R. Kaiser,et al.  Controlled Chemistry via Contactless Manipulation and Merging of Droplets in an Acoustic Levitator. , 2020, Analytical chemistry.

[3]  K. Hasegawa,et al.  Coalescence Dynamics of Acoustically Levitated Droplets , 2020, Micromachines.

[4]  M. Baudoin,et al.  Acoustic Tweezers for Particle and Fluid Micromanipulation , 2020, Annual Review of Fluid Mechanics.

[5]  J. Benlloch,et al.  Generating Bessel beams with broad depth-of-field by using phase-only acoustic holograms , 2019, Scientific Reports.

[6]  J. Mobley,et al.  Broadband wave packet dynamics of minimally diffractive ultrasonic fields from axicon and stepped fraxicon lenses. , 2019, Journal of the Acoustical Society of America.

[7]  Michael Baudoin,et al.  Folding a focalized acoustical vortex on a flat holographic transducer: Miniaturized selective acoustical tweezers , 2018, Science Advances.

[8]  Peng Li,et al.  Acoustic tweezers for the life sciences , 2018, Nature Methods.

[9]  C. Brugnara,et al.  Shape oscillations of single blood drops: applications to human blood and sickle cell disease , 2018, Scientific Reports.

[10]  K. Hasegawa,et al.  Contactless Fluid Manipulation in Air: Droplet Coalescence and Active Mixing by Acoustic Levitation , 2018, Scientific Reports.

[11]  M. Petermann,et al.  Simultaneous measurement of surface tension and viscosity using freely decaying oscillations of acoustically levitated droplets. , 2018, The Review of scientific instruments.

[12]  Robert Malkin,et al.  Three-dimensional ultrasonic trapping of micro-particles in water with a simple and compact two-element transducer , 2017 .

[13]  Anthony J. Croxford,et al.  Realization of Compact Tractor Beams using Acoustic Delay-Lines , 2017 .

[14]  Sriram Subramanian,et al.  Metamaterial bricks and quantization of meta-surfaces , 2016, Nature Communications.

[15]  Peer Fischer,et al.  Holograms for acoustics , 2016, Nature.

[16]  Sriram Subramanian,et al.  Holographic acoustic elements for manipulation of levitated objects , 2015, Nature Communications.

[17]  I-Kao Chiang,et al.  On-chip manipulation of single microparticles, cells, and organisms using surface acoustic waves , 2012, Proceedings of the National Academy of Sciences.

[18]  Eun Sok Kim,et al.  Microparticle trapping in an ultrasonic Bessel beam. , 2011, Applied physics letters.

[19]  Changyang Lee,et al.  Single beam acoustic trapping. , 2009, Applied physics letters.

[20]  S. Manneville,et al.  Deformation of acoustically transparent fluid interfaces by the acoustic radiation pressure , 2008 .

[21]  Philip L Marston,et al.  Manipulation of Fluid Objects with Acoustic Radiation Pressure , 2004, Annals of the New York Academy of Sciences.

[22]  J. Wu,et al.  Acoustical tweezers. , 1991, The Journal of the Acoustical Society of America.

[23]  R Vazquez-Duhalt,et al.  Environmental impact of used motor oil. , 1989, The Science of the total environment.

[24]  R. Apfel,et al.  Acoustically forced shape oscillation of hydrocarbon drops levitated in water , 1979 .

[25]  Lawrence A. Crum,et al.  Acoustic Force on a Liquid Droplet in an Acoustic Stationary Wave , 1971 .