Recent advances of light-driven micro/nanomotors: toward powerful thrust and precise control

Abstract

In the past two decades, micro/nanomotor is emerging as a critical domain of nanoscale research. Light-driven micro/nanomotors have gained a wealth of attention from the academics because of their potential applications in various fields such as environment remediation, biomedical field and cargo delivery at microscale. In order to perform some more challenging and complex tasks, higher actuation force and more precise control are both indispensable for light-driven micro/nanomotors. In this review, we discussed about three major factors: actuation mechanism, structure of micro/nanomotors and the wavelength of light irradiation, to find out how to gain a higher actuation force and propel the motor in a relatively high speed under light irradiation. Besides, some common control strategies of light-driven micro/nanomotors are presented in details with the advantages and disadvantages of each control mechanism, which will help lead to a convenient and precise control. Finally, the future development approaches toward powerful thrust and precise control are discussed for light-driven micro/nanomotors.

Perspective: Ferromagnetic Liquids

“…In this sense, ferromagnetic liquids open up an entirely new world of magnetic materials benefiting from mechanical and magnetic reconfigurability; for instance, 3D printed water-in-oil magnetic liquid tubules offer arbitrary shape (fluidity) and self-adaptive permanent magnetization (solidity), which benefit magnetic liquid actuators, non-contact liquid capsule delivery and other magnetically controlled devices in all-liquid environment. Magnetically driven autonomous technology often relates to the parallelized and sequential operations with respect to actuators in medical diagnostics, non-contact delivery and chemicals synthesis [56][57][58][59][60][61][62][63]. Reconfigurable ferromagnetic liquids representing magnetic liquid actuators and sensors, interact with the external magnetic field to exert translation and precession movement that can be facilitated in analogy to solid-state magnets.…”

“…The overarching questions regarding magnetic sensing with ferromagnetic liquids is the detection of physical changes that is conveniently done by magneto-resistance measurements in exchange-coupled metallic materials. For these applications, electro-chemical plating using a porous alumina template and strain-engineering rolled-up nanotech facilitating intrinsic strain gradients have been employed [60,61] and refined to synthesize nano-rods, nano-tubes and multi-segmented specimens [64][65][66][67][68][69][70] with variable diameter (<50 nm), and microtubules with tailored magnetization configuration [71,72] that achieve unprecedented sensitivity based on the giant magneto-impedance effect [73].…”

Theories for triboelectric nanogenerators: A comprehensive review

“…There are various energy harvesting devices for collecting different types of energies. For example, the piezoelectric effect for mechanical energy harvesting [1], thermal energy harvesters [2], lightdriven micro/nanomotors based on the photothermal effect [3], etc. Moreover, the triboelectric nanogenerator (TENG) is a novel type of mechanical energy capture device based on the triboelectric effect.…”

Recent Advances in Motion Control of Micro/Nanomotors

“…[56] In recent years, as an efficient external energy for driving the micro/nanomotors, light source has been explored in-depth to fulfill an acceptable and satisfactory motility controllability. [57][58][59] Basically, the movement of the light-propelled micro/nanomotors is activated either by photochemical reaction, [60] photothermal effect [61][62][63] or photochromism; [64] both could avoid the utilization of toxic chemical fuels. [65] However, the absence of those chemical fuels leads to a very challenging issue of achieving high velocities for these light-driven micromotors.…”