Control of the radial motion of a self-propelled microboat through a side rudder

Qiao, Lei; Xiao, Di; Lu, Frank K.; Luo, Cheng

doi:10.1016/j.sna.2012.04.004

Cited by 13 publications

(11 citation statements)

References 9 publications

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“…Attaching together two particles into an "L-shape" also introduces a rotational element into the particle's motion (Figure 6d). This is because, in addition to generating the Marangoni effect, the two attached particles act as rudders 48 with respect to each other. Thus, an L-shaped particle's trajectory constitutes a large circle with periodic small swirls over a larger area of the water surface.…”

Section: Resultsmentioning

confidence: 99%

Gel-Based Self-Propelling Particles Get Programmed To Dance

2012

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We present a class of gel-based self-propelling particles moving by the Marangoni effect in an oscillatory mode. The particles are made of an ethanol-infused polyacrylamide hydrogel contained in plastic tubing. These gel boats floating on the water surface exhibit periodic propulsion for several hours. The release of ethanol from the hydrogel takes place beneath the liquid surface. The released ethanol rises to the air-water interface by buoyancy and generates a self-sustained cycle of surface tension gradient driven motion. The disruption of the ethanol flux to the surface by the bulk flows around the moving particle results in their pulsating motion. The pulse interval and the distance propelled in a pulse by these gel floaters were measured and approximated by simple expressions based on the rate of ethanol mass-transfer through and out of the hydrogel. This allowed us to design a multitude of particles performing periodic steps in different directions or at different angles of rotation, traveling in complex preprogrammed trajectories on the surface of the liquid. Similar gel-based self-propelling floaters can find applications as mixers and cargo carriers in lab-on-a-chip devices, and in various platforms for sensing and processing at the microscale.

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Section: Resultsmentioning

confidence: 99%

Gel-Based Self-Propelling Particles Get Programmed To Dance

2012

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“…It can be patterned to desired shapes using ultraviolet lithography. It has functioned as a good structural material in microsystems, such as in gears, boats − and flotillas. , After a liquid drop is put on a plate, the side view of the corresponding equilibrium state is imaged through an optical microscope. The advancing and receding contact angles are measured on the plate by increasing and decreasing the volume of the drop, respectively, until this drop starts to move.…”

Section: Experimental Results and Discussionmentioning

confidence: 99%

Separation of Oil from a Water/Oil Mixed Drop Using Two Nonparallel Plates

Luo

Heng

2014

Langmuir

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In this work, we have developed a simple approach to separate oil from a microliter-scaled water/oil mixture by squeezing the mixture using two nonparallel plates. Three pairs of plates with Teflon, SU-8, and SiO2 coatings, respectively, are used in the tests, and all of these plates are capable of separating the water/oil mixed drops. 95.5% silicone oil and 97.0% light mineral oil have been collected from their corresponding mixtures with water through the pair of Teflon plates. Furthermore, on the basis of pressure difference inside a liquid drop, theoretical models have been developed to interpret the corresponding mechanisms of the separation process, as well as the observed phenomena. To judge whether two immiscible liquids could be separated using the developed approach, a sufficient condition has also been derived, which includes three theoretical relations. The sufficient condition is subsequently validated by experiments. This condition also provides criteria for choosing a good plate coating. Such a coating should ensure (i) the oil wets the plate surface with a relatively large contact angle, and has small contact angle hysteresis, and (ii) the advancing contact angle that the water/oil interface forms on the plate surface is larger than 90°.

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“…Miniaturized self-propulsive devices represent a series of smart materials at the mm-to-cm scale that could be automatically powered by diverse energy including physicochemical reactions, − light/heat, − and magnetic/electric field, − for advanced applications in environmental remediation, − self-assembly, − electricity generation, ,, etc. Among the above devices, Marangoni boats or rotors driven by fluid motions based on the Marangoni effect − have been attractive owing to the unique biomimicking features, − mild motions, , and flexible designs. − The underlying driving force to propel the devices is normally provided by the flows at the interface between two phases with a gradient of surface tension. Two common principles are applied by using different energy sources including the photothermal effect by creating local temperature differences and concentration gradients by releasing surfactants at the interface.…”

Section: Introductionmentioning

confidence: 99%

A Multi-engine Marangoni Rotor with Controlled Motion for Mini-Generator Application

Zhu

Peng

et al. 2023

ACS Appl. Mater. Interfaces

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Marangoni rotors are smart devices that are capable of self-propulsive motions based on the Marangoni effect, namely interfacial flows caused by a gradient of surface tension. Owing to the features of untethered motions and coupled complexity with fluid, these Marangoni devices are attractive for both theoretical study and applications in biomimicking, cargo delivery, energy conversion, etc. However, the controllability of Marangoni motions dependent on concentration gradients remains to be improved, including the motion lifetime, direction, and trajectories. The challenge lies in the flexible loading and adjustments of surfactant fuels. Herein, we design a multi-engine device in a six-arm shape with multiple fuel positions allowing for motion control and propose a strategy of diluting the surfactant fuel to prolong the motion lifetime. The resulting motion lifetime has been extended from 140 to 360 s by 143% compared with conventional surfactant fuels. The motion trajectories could be facilely adjusted by changing both the fuel number and positions, leading to diverse rotation patterns. By integrating with a coil and a magnet, we obtained a system of mini-generators based on the Marangoni rotor. Compared with the single-engine case, the output of the multi-engine rotor was increased by 2 magnitudes owing to increased kinetic energy. The design of the above Marangoni rotor has addressed the problems of concentration-gradient-driven Marangoni devices and enriched their applications in harvesting energy from the environment.

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Control of the radial motion of a self-propelled microboat through a side rudder

Cited by 13 publications

References 9 publications

Gel-Based Self-Propelling Particles Get Programmed To Dance

Gel-Based Self-Propelling Particles Get Programmed To Dance

Separation of Oil from a Water/Oil Mixed Drop Using Two Nonparallel Plates

A Multi-engine Marangoni Rotor with Controlled Motion for Mini-Generator Application

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