Editorial

2 pages, 147 KiB

Open AccessEditorial

Selected Papers from the 2017 International Conference on Micro/Nanomachines

by Fangzhi Mou and Jianguo Guan

Micromachines 2018, 9(6), 284; https://doi.org/10.3390/mi9060284 - 04 Jun 2018

Viewed by 2497

Thanks to their capabilities of converting various energy into motions, micro/nanomachines are believed to bring about revolutionary changes in many fields[...] Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

Research

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11 pages, 3324 KiB

Open AccessArticle

Multiple Electrohydrodynamic Effects on the Morphology and Running Behavior of Tiny Liquid Metal Motors

by Yue Sun, Shuo Xu, Sicong Tan and Jing Liu

Micromachines 2018, 9(4), 192; https://doi.org/10.3390/mi9040192 - 18 Apr 2018

Cited by 12 | Viewed by 3502

Abstract

Minimized motors can harvest different types of energy and transfer them into kinetic power to carry out complex operations, such as targeted drug delivery, health care, sensing and so on. In recent years, the liquid metal motor is emerging as a very promising [...] Read more.

Minimized motors can harvest different types of energy and transfer them into kinetic power to carry out complex operations, such as targeted drug delivery, health care, sensing and so on. In recent years, the liquid metal motor is emerging as a very promising tiny machine. This work is dedicated to investigate the motion characteristics of self-powered liquid metal droplet machines under external electric field, after engulfing a small amount of aluminum. Two new non-dimensional parameters, named

Ä

and

Ö

, are put forward for the first time to evaluate the ratio of the forces resulting from the electric field to the fluidic viscous force and the ratio of the friction force to the fluidic viscous force. Forces exerted on liquid metal droplets, the viscosity between the droplet and the surrounding fluid, the pressure difference on both ends, the friction between the bottom of the droplet and the sink base, and bubble propulsion force are evaluated and estimated regarding whether they are impetus or resistance. Effects of electric field intensity, droplet size, solution concentration and surface roughness etc. on the morphology and running behavior of such tiny liquid metal motors are clarified in detail. This work sheds light on the moving mechanism of the liquid metal droplet in aqueous solutions, preparing for more precise and complicated control of liquid metal soft machines. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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10 pages, 2663 KiB

Open AccessCommunication

Mini-EmulsionFabricated Magnetic and Fluorescent Hybrid Janus Micro-Motors

by Jiapu Jiao, Dandan Xu, Yuhuan Liu, Weiwei Zhao, Jiaheng Zhang, Tingting Zheng, Huanhuan Feng and Xing Ma

Micromachines 2018, 9(2), 83; https://doi.org/10.3390/mi9020083 - 15 Feb 2018

Cited by 11 | Viewed by 5789

Abstract

Self-propelling micro/nano-motors have attracted great attention due to their controllable active motion and various functional attributes. To date, a variety of technologies have been reported for the fabrication of micro/nano-motors. However, there are still several challenges that need to be addressed. One of [...] Read more.

Self-propelling micro/nano-motors have attracted great attention due to their controllable active motion and various functional attributes. To date, a variety of technologies have been reported for the fabrication of micro/nano-motors. However, there are still several challenges that need to be addressed. One of them is to endow micro/nano-motors with multi-functionalities by a facile fabrication process. Here, we present a universal approach, adopted from the emulsion templating method, for the fabrication of Janus micro-motors. With a one-step process, magnetic nanoparticles and fluorescent dyes are simultaneously embedded into the microparticles. The self-propelled motors can be used as an active label or fluorescent tracer through manipulation of their motion using magnetic guidance. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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12 pages, 5396 KiB

Open AccessArticle

Manipulating Microrobots Using Balanced Magnetic and Buoyancy Forces

by Lin Feng, Xiaocong Wu, Yonggang Jiang, Deyuan Zhang and Fumihito Arai

Micromachines 2018, 9(2), 50; https://doi.org/10.3390/mi9020050 - 29 Jan 2018

Cited by 15 | Viewed by 5176

Abstract

We present a novel method for the three-dimensional (3D) control of microrobots within a microfluidic chip. The microrobot body contains a hollow space, producing buoyancy that allows it to float in a microfluidic environment. The robot moves in the z direction by balancing [...] Read more.

We present a novel method for the three-dimensional (3D) control of microrobots within a microfluidic chip. The microrobot body contains a hollow space, producing buoyancy that allows it to float in a microfluidic environment. The robot moves in the z direction by balancing magnetic and buoyancy forces. In coordination with the motion of stages in the xy plane, we achieved 3D microrobot control. A microgripper designed to grasp micron-scale objects was attached to the front of the robot, allowing it to hold and deliver micro-objects in three dimensions. The microrobot had four degrees of freedom and generated micronewton-order forces. We demonstrate the microrobot’s utility in an experiment in which it grips a 200 μm particle and delivers it in a 3D space. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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8 pages, 1743 KiB

Open AccessArticle

Pair Interaction of Catalytical Sphere Dimers in Chemically Active Media

by Jing-Min Shi, Ru-Fei Cui, Jie Xiao, Li-Yan Qiao, Jun-Wen Mao and Jiang-Xing Chen

Micromachines 2018, 9(1), 35; https://doi.org/10.3390/mi9010035 - 17 Jan 2018

Cited by 7 | Viewed by 3585

Abstract

We study the pair dynamics of two self-propelled sphere dimers in the chemically active medium in which a cubic autocatalytic chemical reaction takes place. Concentration gradient around the dimer, created by reactions occurring on the catalytic sphere surface and responsible for the self-propulsion, [...] Read more.

We study the pair dynamics of two self-propelled sphere dimers in the chemically active medium in which a cubic autocatalytic chemical reaction takes place. Concentration gradient around the dimer, created by reactions occurring on the catalytic sphere surface and responsible for the self-propulsion, is greatly influenced by the chemical activities of the environment. Consequently, the pair dynamics of two dimers mediated by the concentration field are affected. In the particle-based mesoscopic simulation, we combine molecular dynamics (MD) for potential interactions and reactive multiparticle collision dynamics (RMPC) for solvent flow and bulk reactions. Our results indicate three different configurations between a pair of dimers after the collision, i.e., two possible scenarios of bound dimer pairs and one unbound dimer pair. A phase diagram is sketched as a function of the rate coefficients of the environment reactions. Since the pair interactions are the basic elements of larger scale systems, we believe the results may shed light on the understanding of the collective dynamics. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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11 pages, 5383 KiB

Open AccessFeature PaperArticle

Hydrophobic Janus Foam Motors: Self-Propulsion and On-The-Fly Oil Absorption

by Xiaofeng Li, Fangzhi Mou, Jingjing Guo, Zhuoyi Deng, Chuanrui Chen, Leilei Xu, Ming Luo and Jianguo Guan

Micromachines 2018, 9(1), 23; https://doi.org/10.3390/mi9010023 - 11 Jan 2018

Cited by 21 | Viewed by 7265

Abstract

In this work, we for the first time have proposed and fabricated a self-propelled Janus foam motor for on-the-fly oil absorption on water by simply loading camphor/stearic acid (SA) mixture as fuels into one end of the SA-modified polyvinyl alcohol (PVA) foam. The [...] Read more.

In this work, we for the first time have proposed and fabricated a self-propelled Janus foam motor for on-the-fly oil absorption on water by simply loading camphor/stearic acid (SA) mixture as fuels into one end of the SA-modified polyvinyl alcohol (PVA) foam. The as-fabricated Janus foam motors show an efficient Marangoni effect-based self-propulsion on water for a long lifetime due to the effective inhibition of the rapid release of camphor by the hydrophobic SA in the fuel mixture. Furthermore, they can automatically search, capture, and absorb oil droplets on the fly, and then be spontaneously self-assembled after oil absorption due to the self-propulsion of the motors as well as the attractive capillary interactions between the motors and oil droplets. This facilitates the subsequent collection of the motors from water after the treatment. Since the as-developed Janus foam motors can effectively integrate intriguing behaviors of the self-propulsion, efficient oil capture, and spontaneous self-assembly, they hold great promise for practical applications in water treatment. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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Review

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18 pages, 47693 KiB

Open AccessReview

Light-Controlled Swarming and Assembly of Colloidal Particles

by Jianhua Zhang, Jingjing Guo, Fangzhi Mou and Jianguo Guan

Micromachines 2018, 9(2), 88; https://doi.org/10.3390/mi9020088 - 19 Feb 2018

Cited by 39 | Viewed by 7409

Abstract

Swarms and assemblies are ubiquitous in nature and they can perform complex collective behaviors and cooperative functions that they cannot accomplish individually. In response to light, some colloidal particles (CPs), including light active and passive CPs, can mimic their counterparts in nature and [...] Read more.

Swarms and assemblies are ubiquitous in nature and they can perform complex collective behaviors and cooperative functions that they cannot accomplish individually. In response to light, some colloidal particles (CPs), including light active and passive CPs, can mimic their counterparts in nature and organize into complex structures that exhibit collective functions with remote controllability and high temporospatial precision. In this review, we firstly analyze the structural characteristics of swarms and assemblies of CPs and point out that light-controlled swarming and assembly of CPs are generally achieved by constructing light-responsive interactions between CPs. Then, we summarize in detail the recent advances in light-controlled swarming and assembly of CPs based on the interactions arisen from optical forces, photochemical reactions, photothermal effects, and photoisomerizations, as well as their potential applications. In the end, we also envision some challenges and future prospects of light-controlled swarming and assembly of CPs. With the increasing innovations in mechanisms and control strategies with easy operation, low cost, and arbitrary applicability, light-controlled swarming and assembly of CPs may be employed to manufacture programmable materials and reconfigurable robots for cooperative grasping, collective cargo transportation, and micro- and nanoengineering. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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26 pages, 21059 KiB

Open AccessReview

Tubular Micro/Nanomotors: Propulsion Mechanisms, Fabrication Techniques and Applications

by Fengjun Zha, Tingwei Wang, Ming Luo and Jianguo Guan

Micromachines 2018, 9(2), 78; https://doi.org/10.3390/mi9020078 - 13 Feb 2018

Cited by 52 | Viewed by 8054

Abstract

Micro/nanomotors are self-propelled machines that can convert various energy sources into autonomous movement. With the great advances of nanotechnology, Micro/Nanomotors of various geometries have been designed and fabricated over the past few decades. Among them, the tubular Micro/Nanomotors have a unique morphology of [...] Read more.

Micro/nanomotors are self-propelled machines that can convert various energy sources into autonomous movement. With the great advances of nanotechnology, Micro/Nanomotors of various geometries have been designed and fabricated over the past few decades. Among them, the tubular Micro/Nanomotors have a unique morphology of hollow structures, which enable them to possess a strong driving force and easy surface functionalization. They are promising for environmental and biomedical applications, ranging from water remediation, sensing to active drug delivery and precise surgery. This article gives a comprehensive and clear review of tubular Micro/Nanomotors, including propulsion mechanisms, fabrication techniques and applications. In the end, we also put forward some realistic problems and speculate about corresponding methods to improve existing tubular Micro/Nanomotors. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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35 pages, 10324 KiB

Open AccessFeature PaperReview

Geometry Design, Principles and Assembly of Micromotors

by Huanpo Ning, Yan Zhang, Hong Zhu, Andreas Ingham, Gaoshan Huang, Yongfeng Mei and Alexander A. Solovev

Micromachines 2018, 9(2), 75; https://doi.org/10.3390/mi9020075 - 11 Feb 2018

Cited by 51 | Viewed by 10319

Abstract

Discovery of bio-inspired, self-propelled and externally-powered nano-/micro-motors, rotors and engines (micromachines) is considered a potentially revolutionary paradigm in nanoscience. Nature knows how to combine different elements together in a fluidic state for intelligent design of nano-/micro-machines, which operate by pumping, stirring, and diffusion [...] Read more.

Discovery of bio-inspired, self-propelled and externally-powered nano-/micro-motors, rotors and engines (micromachines) is considered a potentially revolutionary paradigm in nanoscience. Nature knows how to combine different elements together in a fluidic state for intelligent design of nano-/micro-machines, which operate by pumping, stirring, and diffusion of their internal components. Taking inspirations from nature, scientists endeavor to develop the best materials, geometries, and conditions for self-propelled motion, and to better understand their mechanisms of motion and interactions. Today, microfluidic technology offers considerable advantages for the next generation of biomimetic particles, droplets and capsules. This review summarizes recent achievements in the field of nano-/micromotors, and methods of their external control and collective behaviors, which may stimulate new ideas for a broad range of applications. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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19 pages, 8737 KiB

Open AccessReview

Light-Powered Micro/Nanomotors

by Hongxu Chen, Qilong Zhao and Xuemin Du

Micromachines 2018, 9(2), 41; https://doi.org/10.3390/mi9020041 - 23 Jan 2018

Cited by 66 | Viewed by 9171

Abstract

Designed micro/nanomotors are micro/nanoscale machines capable of autonomous motion in fluids, which have been emerging in recent decades owing to their great potential for biomedical and environmental applications. Among them, light-powered micro/nanomotors, in which motion is driven by light, exhibit various advantages in [...] Read more.

Designed micro/nanomotors are micro/nanoscale machines capable of autonomous motion in fluids, which have been emerging in recent decades owing to their great potential for biomedical and environmental applications. Among them, light-powered micro/nanomotors, in which motion is driven by light, exhibit various advantages in their precise motion manipulation and thereby a superior scope for application. This review summarizes recent advances in the design, manufacture and motion manipulation of different types of light-powered micro/nanomotors. Their structural features and motion performance are reviewed and compared. The challenges and opportunities of light-powered micro/nanomotors are also discussed. With rapidly increasing innovation, advanced, intelligent and multifunctional light-powered micro/nanomachines will certainly bring profound impacts and changes for human life in the future. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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5935 KiB

Open AccessReview

Controllable Swarming and Assembly of Micro/Nanomachines

by Conghui Liu, Tailin Xu, Li-Ping Xu and Xueji Zhang

Micromachines 2018, 9(1), 10; https://doi.org/10.3390/mi9010010 - 29 Dec 2017

Cited by 39 | Viewed by 8310

Abstract

Motion is a common phenomenon in biological processes. Major advances have been made in designing various self-propelled micromachines that harvest different types of energies into mechanical movement to achieve biomedicine and biological applications. Inspired by fascinating self-organization motion of natural creatures, the swarming [...] Read more.

Motion is a common phenomenon in biological processes. Major advances have been made in designing various self-propelled micromachines that harvest different types of energies into mechanical movement to achieve biomedicine and biological applications. Inspired by fascinating self-organization motion of natural creatures, the swarming or assembly of synthetic micro/nanomachines (often referred to micro/nanoswimmers, micro/nanorobots, micro/nanomachines, or micro/nanomotors), are able to mimic these amazing natural systems to help humanity accomplishing complex biological tasks. This review described the fuel induced methods (enzyme, hydrogen peroxide, hydrazine, et al.) and fuel-free induced approaches (electric, ultrasound, light, and magnetic) that led to control the assembly and swarming of synthetic micro/nanomachines. Such behavior is of fundamental importance in improving our understanding of self-assembly processes that are occurring on molecular to macroscopic length scales. Full article

(This article belongs to the Special Issue Selected Papers from 2017 International Conference on Micro/Nanomachines)

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