Flexible and wearable pressure sensors are gaining attention due to their widespread applications in biomedical, intelligent, and smart systems. However, developing highly sensitive sensors for low pressures and wide ranges is still a challenge. In this direction, a flexible PDMS‐based pressure sensor is presented, having hemispherical microstructures to achieve high sensitivity and operation range. Several experiments with various dimensions have demonstrated that the sensor with microstructures of radii 100 μm on a 0.5 mm‐thick substrate shows optimum performance for a low‐pressure range of less than 6 kPa. Further, a finite‐element method‐based simulation has illustrated improvement in the sensor response with the decrease in substrate thickness. In practice, a very thin film of the substrate is not suitable for detecting a wide range of pressure. The presence of microstructures, however, improves the performance. Adding porosity to the substrate further elevates the sensitivity to 9.51 kPa−1 for a low‐pressure range of less than 10 kPa. Even for medium (30–70 kPa) and high‐pressure ranges (40–120 kPa), the sensitivities of the sensor proposed are as high as 0.045 and 0.17 kPa−1, respectively. The proposed sensors show at least an order improvement of sensitivities compared with the prior arts.

The substrate plays an important role in flexible devices and sensors. In this direction, it is observed that elastomeric encapsulation assists the sensor system to deform successfully under stretching. The encapsulation not only makes it flexible but also protects it from environmental factors and mechanical damage. In this paper, a Finite Element Method (FEM) analysis is used to study the mechanical effects on the encapsulated system, which provides insight into the design of a stretchable substrate for flexible electronic systems. Here a serpentine silver electrode is designed on a PET (Polyethylene Terephthalate) substrate, which is then encapsulated by PDMS (Polydimethylsiloxane). With the variation in the ratio of top to bottom encapsulation thickness i.e., Ten1: Ten2, the interfacial stress was studied. The mismatch in Ten1 and Ten2 may result in compressive bending strain, which can be avoided by making Ten1 = Ten2. It is observed from the simulation that, there is a spike in von-mises stress at the interface of the substrate and the encapsulation when stretching mode deformation is applied. Also, this maximum stress varies with the variation in encapsulation thickness. For a range of total encapsulation thickness i.e. TEN = Ten1 + Ten2 = 30 µm to 100 µm, the optimum thickness is found to be 55 µm, for which the spike in interfacial von-mises stress is minimum.

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