Foundations for Soft, Smart Matter by Active Mechanical Metamaterials

Abstract

Emerging interest to synthesize active, engineered matter suggests a future where smart material systems and structures operate autonomously around people, serving diverse roles in engineering, medical, and scientific applications. Similar to biological organisms, a realization of active, engineered matter necessitates functionality culminating from a combination of sensory and control mechanisms in a versatile material frame. Recently, metamaterial platforms with integrated sensing and control have been exploited, so that outstanding non‐natural material behaviors are empowered by synergistic microstructures and controlled by smart materials and systems. This emerging body of science around active mechanical metamaterials offers a first glimpse at future foundations for autonomous engineered systems referred to here as soft, smart matter. Using natural inspirations, synergy across disciplines, and exploiting multiple length scales as well as multiple physics, researchers are devising compelling exemplars of actively controlled metamaterials, inspiring concepts for autonomous engineered matter. While scientific breakthroughs multiply in these fields, future technical challenges remain to be overcome to fulfill the vision of soft, smart matter. This Review surveys the intrinsically multidisciplinary body of science targeted to realize soft, smart matter via innovations in active mechanical metamaterials and proposes ongoing research targets that may deliver the promise of autonomous, engineered matter to full fruition.

Digital logic gates in soft, conductive mechanical metamaterials

“…By establishing interfaces between soft mechanical metamaterials and digital logic gating, this work formulates a general method to synthesize discrete mechanical configurations with conductive networks to govern digital electrical outputs. As one manifestation of soft, smart matter 36 , the mechanical metamaterial building blocks exploited in this work may be considered as building blocks for future soft matter assemblies, such as to realize autonomous soft machines with integrated sensory, actuation, and decision-making functionalities 37 . The concepts embodied in this report are also free of length-scale dependence, by leveraging nominally kinematic rearrangement of cellular solids 32 , and suggest one means to process mechanical stress inputs without need for periodic sensor observation.…”

The Internet of MetaMaterial Things and their software enablers

“…1 (on the right side). The same principle of operation applies to mechanical, acoustic and thermal metamaterials [6].…”

“…Nano-devices can indeed act as the controllers governing the state of the active cells, oering manufacturing versatility and extreme energy eciency. Nonetheless, until nano-IoT becomes a mainstream technology, other approaches can be adopted for manufacturing software-dened metasurfaces, as reported in the related physics-oriented literature [6]. It is also noted that nano-IoT as a general concept is about embedding nano-sized computers into materials in order to augment the penetration level of applications (e.g., sense structural, temperature, humidity changes within a material, rather than just over it, etc.…”

Living Things Are Not (20th Century) Machines: Updating Mechanism Metaphors in Light of the Modern Science of Machine Behavior

“…All biological and artificial materials and machines strike careful but different balances between many competing performance requirements. By drawing on advances in chemistry, materials science, and synthetic biology, a wider range of material, chemical and biotic building blocks are emerging, such as metamaterials and active matter (Silva et al, 2014;Bernheim-Groswasser et al, 2018;McGivern, 2019;De Nicola et al, 2020;Pishvar and Harne, 2020;Zhang et al, 2020), novel chemical compounds (Gromski et al, 2020), and computerdesigned organisms (Kriegman et al, 2020). These new building blocks may in turn allow artificial or natural evolutionary pressures to design hybrid systems that set new performance records for speed, dexterity, metabolic efficiency, or intelligence, while easing unsatisfying metabolic, biomechanical and adaptive tradeoffs.…”