Ultrahigh Sensitivity Flexible Pressure Sensors Based on 3D‐Printed Hollow Microstructures for Electronic Skins

Highlights The iontronic pressure sensor achieved an ultrahigh sensitivity (Smin > 200 kPa−1, Smax > 45,000 kPa−1). The iontronic pressure sensor exhibited a broad sensing range of over 1.4 MPa. Pseudocapacitive iontronic pressure sensor using MXene was proposed. ABSTRACT Flexible pressure sensors are unprecedentedly studied on monitoring human physical activities and robotics. Simultaneously, improving the response sensitivity and sensing range of flexible pressure sensors is a great challenge, which hinders the devices’ practical application. Targeting this obstacle, we developed a Ti3C2Tx-derived iontronic pressure sensor (TIPS) by taking the advantages of the high intercalation pseudocapacitance under high pressure and rationally designed structural configuration. TIPS achieved an ultrahigh sensitivity (Smin > 200 kPa−1, Smax > 45,000 kPa−1) in a broad sensing range of over 1.4 MPa and low limit of detection of 20 Pa as well as stable long-term working durability for 10,000 cycles. The practical application of TIPS in physical activity monitoring and flexible robot manifested its versatile potential. This study provides a demonstration for exploring pseudocapacitive materials for building flexible iontronic sensors with ultrahigh sensitivity and sensing range to advance the development of high-performance wearable electronics.

Download Full-text

Influence of the Porosity of Polymer Foams on the Performances of Capacitive Flexible Pressure Sensors

Sensors ◽

10.3390/s19091968 ◽

2019 ◽

Vol 19 (9) ◽

pp. 1968 ◽

Cited By ~ 11

Author(s):

Sylvie Bilent ◽

Thi Hong Nhung Dinh ◽

Emile Martincic ◽

Pierre-Yves Joubert

Keyword(s):

Experimental Data ◽

Linear Model ◽

Dielectric Material ◽

Pressure Sensors ◽

Volume Ratio ◽

Measurement Range ◽

Polymer Foams ◽

First Order ◽

Non Linear ◽

Flexible Pressure Sensors

This paper reports on the study of microporous polydimethylsiloxane (PDMS) foams as a highly deformable dielectric material used in the composition of flexible capacitive pressure sensors dedicated to wearable use. A fabrication process allowing the porosity of the foams to be adjusted was proposed and the fabricated foams were characterized. Then, elementary capacitive pressure sensors (15 × 15 mm2 square shaped electrodes) were elaborated with fabricated foams (5 mm or 10 mm thick) and were electromechanically characterized. Since the sensor responses under load are strongly non-linear, a behavioral non-linear model (first order exponential) was proposed, adjusted to the experimental data, and used to objectively estimate the sensor performances in terms of sensitivity and measurement range. The main conclusions of this study are that the porosity of the PDMS foams can be adjusted through the sugar:PDMS volume ratio and the size of sugar crystals used to fabricate the foams. Additionally, the porosity of the foams significantly modified the sensor performances. Indeed, compared to bulk PDMS sensors of the same size, the sensitivity of porous PDMS sensors could be multiplied by a factor up to 100 (the sensitivity is 0.14 %.kPa−1 for a bulk PDMS sensor and up to 13.7 %.kPa−1 for a porous PDMS sensor of the same dimensions), while the measurement range was reduced from a factor of 2 to 3 (from 594 kPa for a bulk PDMS sensor down to between 255 and 177 kPa for a PDMS foam sensor of the same dimensions, according to the porosity). This study opens the way to the design and fabrication of wearable flexible pressure sensors with adjustable performances through the control of the porosity of the fabricated PDMS foams.

Download Full-text

Integration of 3D Printed Flexible Pressure Sensors into Physical Interfaces for Wearable Robots

Sensors ◽

10.3390/s21062157 ◽

2021 ◽

Vol 21 (6) ◽

pp. 2157

Author(s):

Kevin Langlois ◽

Ellen Roels ◽

Gabriël Van De Velde ◽

Cláudia Espadinha ◽

Christopher Van Vlerken ◽

...

Keyword(s):

Pressure Distribution ◽

Human Subjects ◽

Pressure Sensors ◽

Poor Performance ◽

Capacitive Pressure Sensor ◽

Upper Arm ◽

Seamless Integration ◽

Dynamic Task ◽

Wearable Robots ◽

3D Printed

Sensing pressure at the physical interface between the robot and the human has important implications for wearable robots. On the one hand, monitoring pressure distribution can give valuable benefits on the aspects of comfortability and safety of such devices. Additionally, on the other hand, they can be used as a rich sensory input to high level interaction controllers. However, a problem is that the commercial availability of this technology is mostly limited to either low-cost solutions with poor performance or expensive options, limiting the possibilities for iterative designs. As an alternative, in this manuscript we present a three-dimensional (3D) printed flexible capacitive pressure sensor that allows seamless integration for wearable robotic applications. The sensors are manufactured using additive manufacturing techniques, which provides benefits in terms of versatility of design and implementation. In this study, a characterization of the 3D printed sensors in a test-bench is presented after which the sensors are integrated in an upper arm interface. A human-in-the-loop calibration of the sensors is then shown, allowing to estimate the external force and pressure distribution that is acting on the upper arm of seven human subjects while performing a dynamic task. The validation of the method is achieved by means of a collaborative robot for precise force interaction measurements. The results indicate that the proposed sensors are a potential solution for further implementation in human–robot interfaces.

Download Full-text

Binary Spiky/Spherical Nanoparticle Films with Hierarchical Micro/Nanostructures for High-Performance Flexible Pressure Sensors

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c18543 ◽

2020 ◽

Vol 12 (52) ◽

pp. 58403-58411

Author(s):

Young-Ryul Kim ◽

Minsoo P. Kim ◽

Jonghwa Park ◽

Youngoh Lee ◽

Sujoy Kumar Ghosh ◽

...

Keyword(s):

High Performance ◽

Pressure Sensors ◽

Nanoparticle Films ◽

Flexible Pressure Sensors

Download Full-text

Flexible pressure sensing film based on ultra-sensitive SWCNT/PDMS spheres for monitoring human pulse signals

Journal of Materials Chemistry B ◽

10.1039/c5tb00653h ◽

2015 ◽

Vol 3 (27) ◽

pp. 5436-5441 ◽

Cited By ~ 29

Author(s):

Yan-Long Tai ◽

Zhen-Guo Yang

Keyword(s):

Pressure Sensors ◽

Pressure Sensing ◽

Prosthetic Limbs ◽

Electronic Skin ◽

Essential Components ◽

Biomedical Diagnostics ◽

Healthcare Monitoring ◽

Flexible Pressure Sensors ◽

Human Healthcare

Flexible pressure sensors are essential components of an electronic skin for future attractive applications ranging from human healthcare monitoring to biomedical diagnostics to robotic skins to prosthetic limbs.

Download Full-text

Tunable In Situ 3D-Printed PVDF-TrFE Piezoelectric Arrays

Sensors ◽

10.3390/s21155032 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5032

Author(s):

Alec Ikei ◽

James Wissman ◽

Kaushik Sampath ◽

Gregory Yesner ◽

Syed N. Qadri

Keyword(s):

3D Printing ◽

Polyvinylidene Fluoride ◽

Vinylidene Fluoride ◽

Mechanical Strain ◽

Pressure Sensors ◽

Strain Ratio ◽

Ex Situ ◽

Order Of Magnitude ◽

3D Printed

In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.

Download Full-text

Multi length scale hierarchical architecture overcoming pressure sensing range-speed tradeoff for flexible pressure sensors

Journal of Materials Chemistry C ◽

10.1039/d1tc03753f ◽

2021 ◽

Author(s):

Qiong Tian ◽

Wenrong Yan ◽

Tianding CHEN ◽

Derek Ho

Keyword(s):

Biomedical Applications ◽

Pressure Sensors ◽

Human Machine Interface ◽

Hierarchical Architecture ◽

Soft Robotics ◽

Length Scale ◽

Pressure Sensing ◽

Sensing Range ◽

Machine Interface ◽

Flexible Pressure Sensors

Pressure sensing electronics have gained great attention in human-machine interface, soft robotics, and wearable biomedical applications. However, existing sensor architectures are inadequate in overcoming the classic tradeoff between sensing range,...

Download Full-text