obtained by the combination of these effects together exhibit more accuracy as com­

pared to the signals achieved by the separate component analysis. Current trends in the

design of flexible and soft artificial hands and limbs, similar to lifelike have led to the

study of the human hand motion in detail. In human hands, mechanoreceptors record

the tactile motion that is processed and understood by the somatosensory cortex. For

data interpretation, the neural system is replaced by artificial mechanoreceptors. Thus

recorded and analyzed tactile information provides information about objects [21].

The tactile gloves are examples of these sensors. The deep convolution networks in­

tegrated into the gloves are used to check the spatial and temporal relationship for

interactive maps. Thus, a tactile glove is used to distinguish the objects and measure

their weights [22].

9.2.2 Skin-Like Stretchable Electronics

Human skin plays an important role to communicate with animals and objects through

its mechanoreceptors. The body can move due to the flexibility and stretchability of the

skin. Mechano-electronic systems bioinspired from the skin are used for robotics and

prosthetics. These receptors are made up of silicon devices that can bend and stretch

the body.

9.2.2.1 Intrinsically Stretchable Materials

The electronic skin requires all the components such as stretchability, flexibility, invariance,

and higher conductivity in the electrode. To mimic the human skin, elastomers and poly­

mers are used as intrinsically stretchable materials. These can elongate equally or larger

(30%) as compared with human skin. Elastomer materials include polyurethane, poly

(dimethylsiloxane) (PDMS), poly (styrene-butadiene-styrene), inorganic and organic ma­

terials (nickel, graphene flakes, and carbon black), and organic polymers have required

intrinsic properties. The incorporation of these materials, for example graphene, as electrode

material increases stretchability (70%) and resistance [23]. The conductivity and stretch­

ability of materials are highly shaped dependent. The irregular dispersion of organic-

inorganic composites causes brittleness and limits stretchability. The implementation of

shape-controlled materials like 1D and 2D enhances the desired properties of biomimetic

devices. These materials improve their conductivity by maintaining the percolation path­

ways and stretchability by reducing the percolation threshold. Silver nanowires and carbon

nanotubes are examples of these materials. The longer the length of nanowires, the better is

the percolation network. However, the smaller density of nanowires improves the trans­

parency and mechanical strength of these nanowires.

9.2.2.2 Extrinsically Stretchable Platforms

Artificially designed structures are used in electronics to achieve stretchability in the circuit

level for electronic skins. Inorganic materials are developed to attain stretchability and

softness just like real skin. Plant tendrils possess the helix, a natural compound. Helix is

more flexible just like gold and copper, due to its 3D structure. It can be wrapped into

stretchable devices like robots, conductors, and smart sprigs [24]. No change in length

occurs due to the stretching of the wires, thus it remains conductive even at connection

points. Helix-containing systems show more conductivity as compared to intrinsically

stretchable materials. The elastomer containing copper helical possesses no variant

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Bioelectronics