Nanomagnetic encoding of shape-morphing micromachines

Abstract

Shape-morphing systems, which can perform complex tasks through morphological transformations, are of high interest for future applications in minimally invasive medicine 1,2 , soft robotics 3-6 , active metamaterials 7 , and smart surfaces 8. With current fabrication methods, shapemorphing configurations have been embedded into structural design, for example by spatially distributing heterogeneous materials 9-14 , which cannot be altered once fabricated. The systems are therefore restricted to a single type of transformation that is predetermined by their geometry. In this work, we have developed a strategy to encode multiple shape-morphing information into a micromachine by programming the magnetic configurations of arrays of single-domain nanomagnets on connected panels. By tailoring the switching fields of the nanomagnets, the magnetic configurations can be programmed using a specific sequence of magnetizing fields and, with customised micromachine designs, these magnetic configurations result in specific shape transformations in an applied magnetic field. Using this concept, we have built an assembly of modular units that can be programmed to morph into alphabetic letters, and we have constructed a microscale 'bird' capable of complex behaviours, including 'flapping', 'hovering', 'turning' and 'side-slipping'. This establishes a route for the creation of future intelligent microsystems that are reconfigurable and reprogrammable in situ, and can therefore adapt to complex situations.

Reprogrammable shape morphing of magnetic soft machines

“…Shape-morphing materials that can be actuated via external stimuli, such as light, temperature, humidity, pH, and acoustic, electrical and magnetic fields, hold great importance for future applications in minimally invasive medicine (1)(2)(3), implantable and wearable devices (4,5), soft robotics (6)(7)(8)(9), and micromachines (10)(11)(12). Magnetically responsive soft materials with programmable shape deformation are particularly desirable for fast, reversible, and complex morphing of soft machines (5,6,10,11,13,14). Magneto-active properties of these soft machines stem from magnetic micro/nanoparticles distributed within a soft polymer matrix.…”

Ferrofluid Droplets as Liquid Microrobots with Multiple Deformabilities

“…However, due to the limitations of feasible soft materials, it is difficult to manufacture functional deformable robots at the micron level and most of them usually only possess a single type of deformation and are unchangeable once they have been fabricated. [ 16 ]…”

Untethered and ultrafast soft-bodied robots

“…The magnetic field is a promising driving force that potentially enables fast actuation 16,23,24 remotely without constraining on-board power sources and control units typically required for untethered robots 25,26 . Such soft robots can be programmed during fabrication 14,[16][17][18][19][20][21][22][27][28][29][30][31] , enabling them to accomplish various tasks. These properties endow magnetic soft robots with the ability to move even in complex environments for biomedical applications such as cell manipulation 21 , drug delivery 32 , and disease diagnosis [33][34][35] .…”