Cooperative Self-Assembled Magnetic Micropaddles at Liquid Surfaces

Abstract

Cooperative controls of magnetic microswimmers are desired for complex micromanipulation and microassembly tasks. Self-assembled magnetic micropaddles as microswimmers that can locomote freely and cooperate at liquid surfaces are proposed inspired by the paddling motion. The micropaddles are self-assembled with metallic disks under a rotating magnetic field, and they are endowed with controlled propulsion in the precessing field. The micropaddles can locomote freely with a maximum speed of approximately 3.3 mm/s and manipulate objects at the liquid surface. It is found that the micropaddles reverse moving directions at high frequencies and that those with different lengths can locomote in opposite directions under the same precessing magnetic field. Based on the distinctive motion properties, not only could several micropaddles combine into the longer ones but a single micropaddle could also be disassembled into two cooperative partners. Assemblies of different parts based on their cooperation are realized in this study, which is challenging for other types of magnetic microswimmers. Micropaddles with adjustable length, flexible locomotion, and cooperative capability present a promising avenue for various micromanipulation applications.

Flexible Magnetic Micropartners for Micromanipulation at Interfaces

“…Micromanipulation Based on Micropartners. Manipulating some cargoes floating at liquid surfaces by pushing or pulling them has been achieved in our previous work using different microrobots, 26,33 where these delivered cargoes cannot escape from the microrobots due to the sufficient capillary attractions. The connected microdisks here can also manipulate microparts in similar ways.…”

“…In contrast, interfacial robots actuated by external stimuli, such as light, ,, electrostatic fields, and magnetic fields, − can have their dimensions down to several micrometers for various micromanipulations. In particular, the magnetically powered microrobots have recently aroused attraction due to their appropriate biological compatibilities and excellent mobolity in enclosed spaces, where efficient actuation and control strategies are the key challenges.…”

Dynamically reversible cooperation and interaction of multiple rotating micromotors

“…Another class of magnetic micromotors can be operated at the liquid-air interface for environmental remediation and micromanipulation, 40,41 and the cooperative or interactive behaviours of multiple magnetic micromotors have also been studied. Two decades ago, Grzybowski et al 42 reported the dynamic interaction of millimetre-sized magnetized disks at the liquid-air interface, in which system the dynamic equilibrium was dominated by hydrodynamic force and magnetic force owing to the magnetic potential produced by a permanent magnet.…”

Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br‐Doped Na3V2(PO4)2F3/C toward Enhanced Sodium Storage

“…To improve the electrical conductivity of Na 3 V 2 (PO 4 ) 2 F 3 , researchers have adopted several effective methods, such as carbon coating, [ 13,14 ] heterogeneous ions doping, [ 15–19 ] and particle nanocrystallization. [ 20 ] Moreover, different preparation methods, including high‐temperature solid‐state method, [ 21 ] sol‐gel method, [ 18 ] solvothermal method, [ 22–24 ] and electrostatic spinning method [ 25,26 ] have been used for the synthesis of Na 3 V 2 (PO 4 ) 2 F 3 . However, none of these methods are effective in obtaining pure phase, which greatly limited its practical application.…”