Three-Dimensional Multifunctional Magnetically Responsive Liquid Manipulator Fabricated by Femtosecond Laser Writing and Soft Transfer

Abstract

Nature-inspired magnetically responsive intelligent topography surfaces have attracted considerable attention owing to their controllable droplet manipulation abilities. However, it is still challenging for magnetically responsive surfaces to realize three-dimensional (3D) droplet/multidroplet transport in both horizontal and vertical directions. Additionally, the droplet horizontal propulsion speed needs to be improved. In this work, a 3D droplet/multidroplet transport strategy based on magnetically responsive microplates array (MMA) actuated by a spatially varying and periodic magnetic field is proposed. The modified superhydrophobic surface can transport droplets rapidly both in horizontal and vertical directions, and it can even realize against-gravity upslope propulsion. The rapid horizontal droplet propulsion (∼58.6 mm/s) is ascribed to the abrupt inversion of the modified surface induced by the specific magnetic field. Furthermore, the nonmagnetically responsive microplates (NMMs)/MMA composite surface is constructed to realize 3D multidroplet manipulation. The implementations of MMA in manipulation of continuous fluids and liquid metal are further demonstrated, providing a valuable platform for microfluidic applications.

Metachronal μ-Cilia for On-Chip Integrated Pumps and Climbing Robots

“…This behavior of the μMAC arrays in a uniform magnetic field offers an alternative solution for creating reversible adhesion, 46 switchable wettability, 47 particle and droplet manipulation, 48 controlled liquid spreading, 49 cell/tissue stimulation by applying stretching and/or squeezing forces on cells, as well as microgrippers. 17 Note that the concentration of the magnetic particles has an important impact on the μMAC behavior and that the bending angle of the μMAC scales nonlinearly with the applied magnetic field.…”

Fabrication and applications of stimuli‐responsive micro/nanopillar arrays

“…Jiang et al reported that a superhydrophobic-coated magnetically responsive microplate array was capable of horizontal transportation and antigravitational capture/ release of the droplet (Figure 12(E-G)). 60 Unlike magnetic fields induced by a single permanent magnet, a periodic magnetic field was induced by employing magnet arrays in which the same magnetic poles faced the same direction. The microplate arrays were fabricated by femtosecond laser writing 174 , heating, soft transfer technology, demolding, and superhydrophobic coating.…”

“…Reproduced with permission. 60 Copyright 2020, American Chemical Society contraction of hydrogel also exemplifies hydrophobicity when heated. 177 Grunlan et al suggested a double network (DN) PNIPAAm hydrogel system to enhance thermosensitivity compared to a single network (SN) hydrogel without increasing the VPTT.…”

“…We examine the working principles of permanently shape-fixable deformation, as well as the reversibly reconfigurable deformation of pillar arrays. Driving forces of the deformations include capillary force-, 36,[40][41][42] light-, [43][44][45][46][47][48][49][50][51][52][53][54] magnetic field, [55][56][57][58][59][60] and thermal sources. [61][62][63][64][65][66][67][68][69][70][71] For example, capillary aggregation is driven by the breaking force balance applied to the adjacent pillars and it is determined by stationary dimensional variables which include width, height and spacing of the pillars.…”

Recent Advances on Nanocomposite Resists With Design Functionality for Lithographic Microfabrication

“…They propose a 3D droplet/multi-droplet transport strategy based on magnetically-responsive microplates array actuated by spatially varying and periodic magnetic field. The modified superhydrophobic surface can transport droplets rapidly both in horizontal and vertical directions, and even realize against-gravity up-slope propulsion (Jiang et al, 2020).…”