**3.3 Polymer conductors and semiconductors**

Polymer conductor and semiconductor are crucial materials for the fabrication of wearable sensors due to their low-cost, solution-processability and easy-chemical modification. Intrinsically flexible electronic materials are building blocks of

#### **Figure 8.**

*(A) Illustration of a thin large-area active-matrix sensor with 12 × 12 tactile pixels. Adapted from Ref. [63]. (B) Schematic illustration of the three-dimensional network structure of the all-nanofiber TENG–based e-skin. The images of the water contact angle and molecular structure of PLGA and PVA are inserted on the top left and lower left, respectively. The surface SEM image of the Ag NW electrode is inserted on the lower right (scale bar, 2* μ*m). Adapted from Ref. [68].*

#### *Advanced Materials and Assembly Strategies for Wearable Biosensors: A Review DOI: http://dx.doi.org/10.5772/intechopen.94451*

wearable sensors which enable scalable and low-cost manufacturing, high-density device integration and large strain tolerance [69, 70].

Kim et al. reported that highly stretchable sensors and transistors that consist of intrinsically stretchable composite semiconductors and conductors [71] as shown in **Figure 9A**. They consist of three main materials: (1) Stretchable semiconductor: P3HT nanofibrils (P3HT-NF)-filled PDMS, (2) Stretchable conductor: PDMS filled with AuNP-AgNW, (3) Stretchable gate dielectric: ions gel. (DoS) electronics are demonstrated (**Figure 9B**), which is deformable, conformal, customizable robust against the human motion. After drawing the electronic ink on desired surfaces, dried ink is strongly attached onto the surface that allows ultra-conformality [72]. Drawn-on-Skin (DoS) electronics were combined with simple fabrication avoiding from dedicated equipment. In addition, these devices can be stacked onto another electronic composite layer on diverse surfaces. Ink, pen, and stencil act as a tool kit for making a variety of DoS electronics that can be mechanically modified and customized to curved textured skins.
