Investigation on the photophoretic lift force acting upon particles under light irradiation

Dong, Shuai; Liu, Yafei

doi:10.1016/j.jaerosci.2017.08.001

Cited by 7 publications

(3 citation statements)

References 22 publications

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“…However, for micrometer‐sized particles, the same force can exceed their weight. Both experimental12,13 and theoretical studies14 have shown the levitation of 1–20 µm diameter spherical particles in mid‐air by using light to create a temperature difference and thus gas flow across the particle surface. The corresponding relative movement of particles and gas is called photophoresis, from Greek words for light and motion.…”

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confidence: 99%

Photophoretic Levitation of Macroscopic Nanocardboard Plates

et al. 2020

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Scaling down miniature rotorcraft and flapping‐wing flyers to sub‐centimeter dimensions is challenging due to complex electronics requirements, manufacturing limitations, and the increase in viscous damping at low Reynolds numbers. Photophoresis, or light‐driven fluid flow, was previously used to levitate solid particles without any moving parts, but only with sizes of 1–20 µm. Here, architected metamaterial plates with 50 nm thickness are leveraged to realize photophoretic levitation at the millimeter to centimeter scales. Instead of creating lift through conventional rotors or wings, the nanocardboard plates levitate due to light‐induced thermal transpiration through microchannels within the plates, enabled by their extremely low mass and thermal conductivity. At atmospheric pressure, the plates hover above a solid substrate at heights of ≈0.5 mm by creating an air cushion beneath the plate. Moreover, at reduced pressures (10–200 Pa), the increased speed of thermal transpiration through the plate's channels creates an air jet that enables mid‐air levitation and allows the plates to carry small payloads heavier than the plates themselves. The macroscopic metamaterial structures demonstrate the potential of this new mechanism of flight to realize nanotechnology‐enabled flying vehicles without any moving parts in the Earth's upper atmosphere and at the surface of other planets.

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confidence: 99%

Photophoretic Levitation of Macroscopic Nanocardboard Plates

et al. 2020

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“…The only vehicles capable of flying in the mesosphere are rockets, but for only minutes at a time ( 1 ). We argue below that photophoresis or light-driven motion ( 7 – 9 ) can potentially provide a no-moving-part mechanism for sustained flight in near space ( 1 , 10 ).…”

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confidence: 98%

Controlled levitation of nanostructured thin films for sun-powered near-space flight

et al. 2021

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We report light-driven levitation of macroscopic polymer films with nanostructured surface as candidates for long-duration near-space flight. We levitated centimeter-scale disks made of commercial 0.5-micron-thick mylar film coated with carbon nanotubes on one side. When illuminated with light intensity comparable to natural sunlight, the polymer disk heats up and interacts with incident gas molecules differently on the top and bottom sides, producing a net recoil force. We observed the levitation of 6-mm-diameter disks in a vacuum chamber at pressures between 10 and 30 Pa. Moreover, we controlled the flight of the disks using a shaped light field that optically trapped the levitating disks. Our experimentally validated theoretical model predicts that the lift forces can be many times the weight of the films, allowing payloads of up to 10 milligrams for sunlight-powered low-cost microflyers at altitudes of 50 to 100 km.

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“…Manipulation of micro-scale objects by laser is a popular technique in biochemical research, which includes photo-induced dielectrophoresis (DEP) [8][9][10][11][12][13][14] and electrophoresis (EP), [15][16][17] as well as optical tweezers [18][19][20] and photophoresis (PP). [21][22][23][24][25][26][27] The manipulation of the DEP force is achieved through the polarization of the dielectric material by the non-uniform electric field. Gao et al achieved the laser-induced condensation of water vapor on LiNbO 3 :Fe (LN:Fe) crystals, 8) demonstrating the attractive effects of dielectric fluid in the LN:Fe-based photovoltaic field due to the DEP force and the auxiliary role of the photovoltaic field in the change of state.…”

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Laser-induced crystallization of fluoranthene in both vapor and solution media

Cao

Gao

Liu

et al. 2023

Appl. Phys. Express

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Organic single crystals are attracting enormous attention and playing an indispensable role in the realization of high-performance electronic devices. In this paper, we reported an in-situ growth method for two-dimensional branch-like and hexagonal shapes fluoranthene crystals under the photophoretic and dielectrophoretic forces generated by the photothermal and photovoltaic effects in both vapor- and liquid- environments. The crystals grown via this method are characterized by the real-time controllability and large size. At the same time, the crystal morphology can also be modified through non-contact illumination. This growth method may serve the future demand for the crystal growth in different phases.

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Investigation on the photophoretic lift force acting upon particles under light irradiation

Cited by 7 publications

References 22 publications

Photophoretic Levitation of Macroscopic Nanocardboard Plates

Photophoretic Levitation of Macroscopic Nanocardboard Plates

Controlled levitation of nanostructured thin films for sun-powered near-space flight

Laser-induced crystallization of fluoranthene in both vapor and solution media

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