# Electrospun Nanofibers for Integrated Sensing, Storage, and Computing Applications
## 5 Applications of Electrospinning in Sensors: Various Sensing Electronics  
As the most popular two-terminal devices, sensors have been widely used in the field of industrial production, smart homes, environmental protection, health monitoring, and so on. Lately, an emerging development trajectory in sensors focuses on their flexibility and  
Figure 16: Non-volatile memory device with resistive memory behavior and their electrospun nanofiber-based application. (**a–d**) Ag/f-MWCNTs-TiO\({}_{2}\) nanofibers/FTO device and its bipolar resistive switching (RS) behavior: (**a**) Device construction of the composite NF-based memory cell. (**b**) I–V characteristic of the Ag/f-MWCNTs-TiO\({}_{2}\)/FTO cell. (**c**) Endurance and (**d**) retention property of the Ag/f-MWCNTs-TiO\({}_{2}\)/FTO memristive device. Reprinted with permission from Reference [112]. Copyright 2020 Elsevier Ltd. (**e–h**) Ag/cellulose fibers/Al memory device and its great endurance and data retention capability: (**e**) Typical device structure of cellulose fiber-based memory device. (**f**) I–V characteristics of the organic memory device. (**g**) Endurance and (**h**) retention memory properties of Ag/cellulose fibers/Al memory device. Reprinted with permission from Reference [113]. Copyright 2018 Elsevier B.V. (**i**) I–V characteristic of the Ag/CGMFs/FTO device in linear scale. Reprinted with permission from Reference [114]. Copyright 2019 Springer Science Business Media, LLC, part of Springer Nature. stretchability, and the electrospinning technique precisely has potential in this field as a result of its large surface-to-volume ratio, high tortuosity, high permeability, high porosity, and portable nature, especially providing strain and pressure sensors. Compared with other metal oxide materials, conductive and piezoelectric polymers prevail because they can exploit deformations induced by small forces. For instance, [PERSON] and his group fabricated a nanomesh skin-strain gauge with breathable, ultrathin, and soft characteristics to continuously monitor skin strain without disturbing [117], and the electrospinning method was used for this nanomesh to produce the compact polyurethane (PU) nanofibers with extremely thin PDMS to reinforce the whole structure. The sensor was incredibly thin (430 nm) and ultralightweight (0.012 mg/cm\({}^{2}\)), which enable the sensor to stick to the skin and detect minute skin strains (Figure 17a). Distinguishable sweat pores cam be seen from the microscopic images of nanomeshes on the surface of artificial skin in Figure 17b and the as-fabricated sensor showed high mechanical durability (resistance degradation lower than 3% after 5000 repeating stretching and releasing cycles) and excellent sustainability (smaller than 5.3% electrical drift error under 40% strain for 12 h). With the unique properties of monitoring signals affecting the natural movement of the skin, the nanomesh sensor was harmlessly attached to the human face and successfully measured the facial strains during speech as shown in Figure 17c. The skin strain distribution on the right side of the face appeared to be symmetrical to the left side of the face with the black markers, indicating that these nanomesh devices accurately reflected actual skin deformations, and allowing the skin to be strained and compressed freely during speech. Furthermore, this device was proven to be capable of detecting stable full-range facial movements, e.g., joy, anger, sadness, fear, and other facial micro-expressions in real-time. This work demonstrated the great potential for the electrospinning technique to produce cutting-edge electronic skins (e-skins) and limitless possibilities to create more and more practical wearable electronic devices simply by electrospinning. Additionally, through the electrospinning technique, researchers prepared an aligned thermoplastic polyurethane (TPU) fibrous mat, then induced CNTs to wrap around the TPU mat through ultrasonication [118] (Figure 17d,e).