Electromechanically Active As‐Electrospun Polystyrene Fiber Mat: Significantly High Quasistatic/Dynamic Electromechanical Response and Theoretical Modeling

Abstract

Flexible and lightweight pressure sensors have attracted tremendous attention as a promising component of wearable biological motion sensors and artificial electronic skins. Here, the electromechanical response of as‐electrospun fiber mats composed of a commodity polymer, atactic polystyrene, which can be applied in low‐cost/large‐area, flexible, and lightweight pressure sensors is demonstrated. The fiber mat demonstrates a significantly high apparent converse piezoelectric constant of >30 000 pm V−1 under static measurement and ≈13 000 pm V−1 even at a high frequency of 1 kHz. The first theoretical model to explain the unique electromechanical response is constructed, which reveals that the softness and moderate charge of the fiber mat are the reasons for the significantly high electromechanical response. Further, apparent piezoelectric constants obtained by direct measurement are lower than those obtained by the converse measurement, which is attributed to the densification and hardening of the fiber mat due to prepressure applied in direct measurement. These findings are likely to serve as a milestone for the development of large‐area, flexible, and lightweight pressure sensors at low cost, as well as highly movable actuators like optical modulators without a substantial mechanical load.

Shear Mode Ultrasonic Transducers from Flexible Piezoelectric PLLA Fibers for Structural Health Monitoring

“…The extrinsic response in the PLLA fiber mat may be related to the space charges and electrostatic effect present in the porous structure from the electrospinning process, which contributes to the piezoelectric response at low frequencies. [60][61][62] Moreover, to examine the coupling effect between the PLLA fibers mat and a substrate, additional investigations were carried out. Here, we attempted to use the LSV method to observe the shear displacement from the PLLA fibers mat bonded to a steel substrate (1.6 mm thick), as shown in Figure S8a (Supporting Information).…”

Fabrication of Pressure Sensor Using Electrospinning Method for Robotic Tactile Sensing Application

“…Among all sensor types, piezoelectric-based pressure sensors are autonomously powered, which generate a consistent electrical signal in response to applied force/pressure. Hence the piezoelectric-type sensor represents a prominent, stand-alone and self-reliant sensor, which makes it suitable for robotic tactile sensing to provide reliable electrical inputs for robotic manipulators [ 13 ].…”

Mask‐Type Acoustic Sensor Featuring a Conventional Disposable Mask Embedded with Electrospun Poly(styrene) Fiber Mats

“…This is because they can self-generate power in response to acoustic/respiration pressure and also exhibit light weight, mechanical flexibility, and breathability. [11] Additionally, the nonwoven mats of charged nano/microfibers can help fabricate high-performance electret filters. [12][13][14] These mats have been employed as acoustic sensor elements in several studies (Table 1).…”

“…Our group discovered that electrospun nonwoven microfiber mats of atactic poly(styrene) (aPS), which typically do not exhibit the piezoelectric effect in film form, exhibit direct/converse electromechanical properties that closely resemble the direct/ converse piezoelectric effect. [11,23] The aPS fiber mats exhibited a significantly high apparent piezoelectric constant d app (d app ≤ 2894 pC N À1 and d app > 30 000 pm V À1 , as determined via quasistatic direct and quasistatic converse electromechanical characterization, respectively). [11] The electromechanical properties evidently originate from the ferroelectret behavior of the aPS fiber mats caused simply by electrospinning.…”

“…[11,23] The aPS fiber mats exhibited a significantly high apparent piezoelectric constant d app (d app ≤ 2894 pC N À1 and d app > 30 000 pm V À1 , as determined via quasistatic direct and quasistatic converse electromechanical characterization, respectively). [11] The electromechanical properties evidently originate from the ferroelectret behavior of the aPS fiber mats caused simply by electrospinning. [11] Notably, the electrospun aPS fiber mats require no post-charging treatments such as poling, leading to lower manufacturing costs than those of the nano/microfiber mats requiring post-charging.…”