conductivity even at 170% stretching [25]. These elastomers are used in microelectronic

systems, where conductivity is most important. Deposition of a conductive and flexible

device on elastomer as substrate results in the buckled electrical conductor. The contraction

in the flexible device is observed, as the strain is released at its normal phase. Flexible

devices made from composite material can be stretched safely without disturbing the

flexibility and conductivity of the device. Many materials like silver, gold, and graphene-

based composites have attained flexibility and stretchability by buckling method that en­

ables their use in wide applications like sensors and electrode materials. Compressing

buckling can be used for the fabrication of scalable sensors array (Figure 9.3) of 3D micro/

nanostructures from their 2D precursors [26].

9.2.3 Multifunctional Electronic Skin as Interactive Interfaces

The use of electronic skin in human skin and prosthetic limbs has been encouraged for

past decades. In prosthetic limbs, electronic skin restores the sense of touch that needs

different types of sensing functionalities integrated on the substrates. The feeling of hu­

midity and temperature along with detection of pressure, the use of biodegradable and

self-healing materials are more favored. The development of flexible electronics with

human skin provides more functionalities and provide look lifelike.

9.2.3.1 Electronic Skins for Human

Electronic skin acts as a bridge between the internal organs of the human body and

machines or computers. Some of the functionalities like detection of body movements,

monitoring of physiological signals, and a human-machine interface can be taken by

artificial interfaces. Bold pressure can be recorded by tactile sensors that provide im­

portant information for clinical and diagnosis purposes. Similarly twisting, bending, and

stretching of the limb can be detected by using strain sensors. The movement of the

robotic limbs is controlled by the signals transmitted from the e-skin to the various parts

of the body to respond to the various stimuli. Epidermal electronics and wearable skin

FIGURE 9.3

A network of 3D piezoresistive sensors. Adapted with permission [ 26]. Copyright 2019, American Chemical Society.

Bioinspired Prosthetic Interfaces

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