(Figure 9.4) have a network structure in their first version, integrated with the stretchable

sensor circuits of multifunctionality.

9.2.3.2 Electronic Skins for Prosthesis

A sensory network is needed for the restoration of a sense of touch through the rigid

prosthesis. Temperature and force sensing can be achieved by direct attachment of sen­

sors with a prosthetic device. The attached fingertip interacts with temperature and

pressure as external stimuli and grasps the information. However, a small interactive area

limits this method. An increase in the number of sensors at different locations can provide

better detection on a prosthetic device. Lack of softness and tactile feedback can be

overcome by using a large area, multifunctional, and scalable interface. One example of

prosthetic hand material is silicon nanoribbon encapsulated by PDMS. External stimuli

are sensed by different sensors for stimuli like pressure, humidity, temperature, and

strain. This study demonstrated that nerves were stimulated by the signals transmitted

from the pressure sensor and responsive signal was recorded. In this approach, complex

integrated materials and devices are needed. The semiconducting ultrathin nanomem­

brane is one of the materials that is easy to handle and are successfully conformed onto a

hand compared to the conventional method, based on direct wrapping [28]. The gloves

are another medium to incorporate the sensors. These gloves are laminated with an ar­

tificial and heated skin layer. This skin layer contains the skin tones, and fingertip tex­

tures just like the real human hand to attain all the attributes of the hand (Figure 9.5) [29].

9.2.4 Self-Healing and Biodegradability

The ability to biodegrade and self-healing makes the construction of prosthetic skins full

of sensations. Recently devices with full healing have been introduced that have pro­

prietors of self-healing even in drastic conditions. Ionic liquids and polymer matrix have

ion-dipole forces that help the self-healing under acidic, wet, and basic conditions.

Supramolecular gels have the ability to self-healing. Carbon nanotubes-based networks in

combination with polymers provide a high self-healable system. A multifunction and

integrated system of an electrocardiogram sensor, strain sensor, and a light-emitting

capacitor is an example of a self-healable system. Transient electronics are an eco-friendly

class of electronics for future use.

FIGURE 9.4

Multifunctional electronic skin. Adapted with permission [ 27]. Copyright 2018, Nature Publishing Group.

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