# Electrospun Nanofibers for Integrated Sensing, Storage, and Computing Applications
## 5 Applications of Electrospinning in Sensors: Various Sensing Electronics
This aligned CNTs/TPU fibrous strain sensor had a vertically aligned wave-like structure with ultra-high stretchability (900%) and excellent durability (10,000 cycles at the strain of 200%) (Figure 17f). The ultra-low detection limit (0.5%) and fast response time of 70 ms were also achieved, exhibiting a favorable sensitivity. Above fine sensing, performances were mainly due to the planned wave-like and joint fiber structure. Thus, the strain sensors were promising candidates for wearable devices to monitor real-time human activities. Except for strain sensors, pressure sensors are also critical for the accurate measurement of small normal pressures to precisely monitor the external force on the dynamic human skin. There are various types of well-developed pressure sensors, e.g., capacitive [119], resistive [120], triboelectric [121], and piezoelectric [122]. Among all these sensors, resistive ones are the most easily fabricated and cost-effective types and hundreds of thousands of studies have been made in the past few decades. For example, stretchable resistive carbon nanotubes-embedded nanofiber sensing yams were successfully prepared by a facile electrospinning technique and proved mechanically robust enough to be woven to a wearable textile sensor capable of distinguishing numerous mechanical inputs, such as pressure, stretching, and bending [120]. Delicate sensing micro/nanostructures and efficient conductive networks endow the sensors with high-pressure sensitivity (12.3 N\({}^{-1}\)), a wide sensing range (around 0.001-5 N), high durability over more than 10,000 cycles, as well as high gauge factors (114-720) over a large stretch range (0.1-220%). Besides, a piezoelectric sensor based on electrospun aligned nanofibrous arrays of poly(vinylidene-fluoride-co-trifluoroethylene) (P(VDF-TrFE)) was reported with an average diameter of 260 nm [123] (Figure 17g). With overall porosity of 65%, the three-dimensional nanofibers had excellent flexibility and were easy to bend (Figure 17i). The ultimate sensors offered exceptional piezoelectric characteristics, allowing for ultra-high sensitivity for pressure measurement, even at extremely small values (0.1 Pa). Electrospun nanofibers with large specific surface area, good biocompatibility, and the ability to specifically detect biological molecules or chemical compounds have been widely researched for sensor applications, such as biosensing or gas sensing. For example, a new electrochemical biosensor based on functional composite nanofibers was created for the sensitive hybridization detection of the p53 tumor suppressor using methylene blue (MB)  
Figure 17: Sensing application for electrospinning methods. (**a**–**c**) Flexible/stretchable strain sensors from electrospun nanofibers: (**a**) Picture of nanomesh sensor attached to a fingerprint. (**b**) Micrographs of nanomeshes on the surface of artificial skin and distinct sweat pores are revealed. (**c**) Facial strain monitoring during the speech. The nanomesh-attached face (right side) exhibits skin strain mapping comparable to that of a face (left side) without nanomeshes. Reprinted with permission from Reference [117]. Copyright 2020 American Association for the Advancement of Science. (**d**–**f**) Illustration of the preparation process of aligned CNTs/TPU mats and CNTs/TPU strain sensor with superior performance: (**d**) Illustration of the pure aligned TPU fibrous network, (**d**\({}^{\prime}\)**) Depiction of a pure TPU mat, and (**d**\({}^{\prime\prime}\)**) SEM image of pure TPU fibers, the white circle represents a joint between two TPU fibers. (**e**) Illustration of CNTs/aligned TPU fibrous network, (**e**\({}^{\prime}\)**) Depiction, and (**e**\({}^{\prime\prime}\)**) SEM image of the CNTs/TPU strain sensor. (**f**) The sensing performance of the strain sensor in 10,000 stretching-releasing cycles towards a strain from 0 to 200% and the insets represent the sensing behaviors in 3000-3010 and 7000-7010 cycles. Reprinted with permission from Reference [118].