Table 2 A summary of the characteristics of mechanical metamaterials beyond mechanical properties and their main functionalities

From: Mechanical metamaterials and beyond

Programmability

 

Functionality beyond mechanical properties

 

Energy harvesting and sensing

Soft robotics

Scientific computation

Integrated system

Actuation

• Tactile sensors5

• magnetic-based transduction method5

• Multiple sensitivity regimes5

• High design degrees of freedom5

• Programmable actuation of metastructures103

• Artificial muscle103

• Temperature-dependent switching and information encryption103

• A tileable mechanical metamaterial with stable memory at the unit-cell level128

• Magnetic actuation128

• Reprogrammability128

• Origami-inspired 3D programmable metamaterials79

• Actuating of unit cells79

• Deployable space structures79

• SMP-hydrogel stent to deliver drugs131

Responsiveness

• Easy-to-manufacture soft tactile sensor5

• 3D printing5

• Multiple desired sensitivities5

• Electro-responsive active metamaterials (e.g., SMPs, SMAs, dielectric elastomers of electroactive polymers, etc.)131

• Magneto-responsive active metamaterials131

• Light-responsive active metamaterials131

• A bi-stable logic-gate elastic metamaterial22

• Wave logic operations22

• Active regulation without continuous-consuming energy22

• Dynamic smart shape transformation32

• Thermal or photothermal trigger32

• Mechanical actuators32

Adaptability

• Multi-layer structure; Multiple perfect absorption bands180

• Solar energy harvesting180

• Reconfigurable structures composed of multistable unit cells139

• 2D graded structures exhibiting serpentine motion139

• Cellular mechanical metamaterials composed of conductive polymers181

• Digital logic gates and gate assemblies181

• Adaptive mechanical properties181

• 4D printing181

• LED integrated device181

• Biomedical scaffold181

Autonomy

• Molecular self-assembly of block copolymers (BCPs)182

• Origami-inspired structures80

• Mechanical self-folding technique80

• Microrobots80

• Reprogrammable mechanological metamaterials129

• Electromagnetic excitation129

• Mechanical systems with embedded intelligence129

• Mechanical adjustable medical stent183

• Radial expansion ability enhancing183

Responsiveness

 

Applications beyond mechanical properties

 

Energy harvesting and sensing

Soft robotics

Scientific computation

Integrated system

Magnetic

• Multistable mechanical metamaterials composed of multiple magnets systems65

• Energy trapping65

• Cilia-inspired soft robots144

• Programmable magnetization patterns144

• Magnetic actuation144

• Magneto-mechanical metamaterials135

• Shape and property tunability135

• Coupled magneto-mechanical actuation135

• A tileable mechanical metamaterial with stable memory at the unit-cell level128

• Magnetic actuation128

• Reprogrammability128

• Cellular metamaterials184

• Magneto-elastic coupling184

• Omni-directional, multi-modal energy absorption in a low-density, tunable, and re-usable platform184

• Magnetic field responsive mechanical metamaterials185

• Dynamic control and on-the-fly tunability185

Electrical

• Kirigami/origami structures59,61

• Triboelectric nanogenerators (TENG)59,61

• Self-aware composite mechanical metamaterials12

• Self-powering and self-sensing blood vessel stents and shock absorbers12

• Electro-responsive active metamaterials (e.g., SMPs, SMAs, dielectric elastomers of electroactive polymers, etc.)131

• Robot fabric131

• Micrometer-scale origami quadruped robot131

• Metamaterial enabled high-speed micro-robot with self-sensing186

• Conductive polymers23

• Digital logic gates and gate assemblies23

• Frequency coding metamaterials121

• Electromagnetic energy radiations control121

• Lamellar ferroelectric metamaterials68

• Excellent printability68

• High piezoelectric behaviors68

• Smart biological systems68

• Triboelectric nanogenerator-enabled structural elements60

• Civil infrastructure monitoring systems60

Thermal

• Broadband thermal energy extraction187

• Hyperbolic metamaterials187

• High near-field thermal energy transfer rate187

• Self-triggered thermomechanical metamaterials15

• Temperature-induced microgrippers15

• Temperature-responsive multistable metamaterials15

• Autonomous actuation and adaptation to the environment15

• Chemical logic gates188

• Standalone systems to analyze different stimuli188

• Thermomechanically triggered two-stage pattern switching of 2D lattices189

Light-driven

• Thermophotovoltaics energy conversion107

• Frequency-selective surface107

• Metamaterial emitters107

• Broadband and omnidirectional hot electron photodetectors190

• Metamaterial perfect absorbers190

• Light-responsive film actuators131

• 2D-to-3D structural transformations131

• Bionic micro-robots131

• Photonic computing191

• Photo-responsive supramolecular polymers192

• Frequency reconfigurable and programmable antennas131

• Five more different working modes and programmable frequency reconstruction191

• Light-driven soft actuators192

• Light-triggered electronic devices192