Fabric-like Electrospun PVAc–Graphene Nanofiber Webs as Wearable and Degradable Piezocapacitive Sensors

Abstract

Flexible piezocapacitive sensors utilizing nanomaterial−polymer composite-based nanofibrous membranes offer an attractive alternative to more traditional piezoelectric and piezoresistive wearable sensors owing to their ultralow powered nature, fast response, low hysteresis, and insensitivity to temperature change. In this work, we propose a facile method of fabricating electrospun graphene-dispersed PVAc nanofibrous membrane-based piezocapacitive sensors for applications in IoT-enabled wearables and human physiological function monitoring. A series of electrical and material characterization experiments were conducted on both the pristine and graphene-dispersed PVAc nanofibers to understand the effect of graphene addition on nanofiber morphology, dielectric response, and pressure sensing performance. Dynamic uniaxial pressure sensing performance evaluation tests were conducted on the pristine and graphene-loaded PVAc nanofibrous membrane-based sensors for understanding the effect of two-dimensional (2D) nanofiller addition on pressure sensing performance. A marked increase in the dielectric constant and pressure sensing performance was observed for graphene-loaded spin coated membrane and nanofiber webs respectively, and subsequently the micro dipole formation model was invoked to explain the nanofiller-induced dielectric constant enhancement. The robustness and reliability of the sensor have been underscored by conducting accelerated lifetime assessment experiments entailing at least 3000 cycles of periodic tactile force loading. A series of tests involving human physiological parameter monitoring were conducted to underscore the applicability of the proposed sensor for IoT-enabled personalized health care, soft robotics, and nextgeneration prosthetic devices. Finally, the easy degradability of the sensing elements is demonstrated to emphasize their suitability for transient electronics applications.

Nanomaterials‐Based Bioinspired Next Generation Wearable Sensors: A State‐of‐the‐Art Review

“…Recently, Sengupta et al reported graphene-polyvinyl acetate (PVAc) nanofiber-based degradable piezocapacitive sensors for human physiological parameters monitoring. [102,113] Similar to the work of Sharma et al, [19] this work fundamentally investigated the effect of 2D nanomaterial filler (graphene) addition on the dielectric constant of PVAc polymer. The sensor reported in the work featured a nanofibrous membrane sandwiched between two layers of circular silver-plated nylon fabric electrodes and optically clear adhesive plate seals for complete encapsulation as shown schematically in Figure 8l.…”

“…Plot showing the sensor responses from the bilateral hamstring, scapula, and gluteal muscle region of a test subject while being seated upright. [102] Reproduced under the terms of the Creative Commons CC BY 4.0 license. [102] Copyright 2023, the Authors, published by ACS.…”

“…[102] Reproduced under the terms of the Creative Commons CC BY 4.0 license. [102] Copyright 2023, the Authors, published by ACS.…”

“…n) Plot showing the sensor responses from the heel regions of a healthy subject while walking with a normal gait. Plot showing the sensor responses from the bilateral hamstring, scapula, and gluteal muscle region of a test subject while being seated upright [102]. Reproduced under the terms of the Creative Commons CC BY 4.0 license [102].…”

Keratin- and VEGF-Incorporated Honey-Based Sponge–Nanofiber Dressing: An Ideal Construct for Wound Healing

“…are some of the widely used forms of dressing materials. Sponges with appropriate gas exchange, acceptable mechanical properties, favorable interconnected pore size, and a noticeable capability of fluid absorption and holding are widely used as a suitable wound dressing. , Additionally, the nanofibrous electrospun membrane is also extensively utilized as a functional structure for wound treatment as it provides a high surface area, mimics the extracellular matrix (ECM), has outstanding mechanical properties, and has exceptional and adaptable chemical, physical, and biological properties. – The main drawback of single-layer wound dressings is that they cannot imitate the hierarchical structure of the skin and provide all clinical needs. , Sponge matrices are preferable to thin membranes for healing full-thickness wounds, but on the other hand, nanofibrous membranes have an ECM-like structure and are more suitable for cell adhesion and proliferation. Therefore, by creating a nanofibrous layer under the sponge matrix, the advantages of both structures can be achieved .…”