3D-Printed Liquid Metal-based Stretchable Conductors and Pressure Sensors

2021 ◽  
Author(s):  
Thassyo Pinto ◽  
Claudia Chen ◽  
Cody Pinger ◽  
Xiaobo Tan
Keyword(s):  
Liquid Metal ◽  
Pressure Sensors ◽  
Stretchable Conductors ◽  
3D Printed

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

Sensors ◽  
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.

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

Sensors ◽  
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.

Self-healing and stretchable conductor based on embedded liquid metal patterns within imprintable dynamic covalent elastomer

2022 ◽  
Author(s):  
Xiaoliang Chen ◽  
Peng Sun ◽  
Hongmiao Tian ◽  
Xiangming Li ◽  
Chunhui Wang ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Electronic Devices ◽  
Electronic Systems ◽  
Self Healing ◽  
Next Generation ◽  
Critical Elements ◽  
Stretchable Conductors ◽  
Stretchable Conductor

Flexible and stretchable conductors are critical elements for constructing soft electronic systems and have recently attracted tremendous attention. Next generation electronic devices call for self-healing conductors that can mimic the...

Flexible Strain Sensor Using Additive Manufacturing and Conductive Liquid Metal: Design, Fabrication, and Characterization

2018 ◽  
Author(s):  
Austin Smith ◽  
Hamzeh Bardaweel
Keyword(s):  
3D Printing ◽  
Liquid Metal ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Limiting Factor ◽  
Successful Implementation ◽  
Conductive Liquid ◽  
Fused Deposition ◽  
3D Printed ◽  
Flexible Strain Sensor

In this work a flexible strain sensor is fabricated using Fused Deposition Modeling (FDM) 3D printing technique. The strain sensor is fabricated using commercially available flexible Thermoplastic Polyurethane (TPU) filaments and liquid metal Galinstan Ga 68.5% In 21% Sn 10%. The strain sensor consists of U-shape 2.34mm long and 0.2mm deep channels embedded inside a TPU 3D printed structure. The performance of the strain sensor is measured experimentally. Gauge Factor is estimated by measuring change in electric resistance when the sensor is subject to 13.2% – 38.6% strain. Upon straining and unstraining, results from characterization tests show high linearity in the range of 13.2% to 38.6% strain with very little hysteresis. However, changes due to permanent deformations are a limiting factor in the usefulness of these sensors because these changes limit the consistency of the device. FDM 3D printing shows promise as a method for fabricating flexible strain sensors. However, more investigation is needed to look at the effects of geometries and 3D printing process parameters on the yield elongation of the flexible filaments. Additionally, more investigation is needed to observe the effect of distorted dimensions of the 3D printed channels on the sensitivity of the strain sensor. It is anticipated that successful implementation of these commercially available filaments and FDM 3D printers will lead to reduction in cost and complexity of developing these flexible sensors.

scholarly journals 3D Printed Flowmeter Based on Venturi Effect with Integrated Pressure Sensors

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1509 ◽  
Author(s):  
Krzysztof Adamski ◽  
Bartosz Kawa ◽  
Rafał Walczak
Keyword(s):  
Liquid Flow ◽  
Pressure Sensors ◽  
Differential Pressure ◽  
Single Chip ◽  
Flow Meter ◽  
Modular Systems ◽  
Venturi Effect ◽  
3D Printed

In this paper we present a 3D printed flow meter based on venturri effect. Dimensions of the microchannels are 800 µm for wider and 400 µm for thinker channel. Application of different type of sensors was investigated: differential, absolute and digital barometer. Results of measurement of differential pressure and calculation of liquid flow are shown. Presented microfluidics device can be also easy adapted for modular systems. Presented flow meter is the first integration of commercial available sensors and 3D printed microfluidics structure in a single chip.

The Effects of Additive Manufacturing and Electric Poling Techniques on PVdF Thin Films: Towards 3D Printed Functional Materials

2020 ◽  
Author(s):  
Jinsheng Fan ◽  
David Gonzalez ◽  
Jose Garcia ◽  
Brittany Newell ◽  
Robert A. Nawrocki
Keyword(s):  
Thin Films ◽  
Smart Materials ◽  
Vinylidene Fluoride ◽  
Pressure Sensors ◽  
Functional Materials ◽  
Piezoelectric Constant ◽  
Β Phase ◽  
Calibration Curves ◽  
Wide Range ◽  
3D Printed

Abstract Mechanical flexibility, faster processing, lower fabrication cost and biocompatibility enable poly (vinylidene fluoride) (PVdF) to have a wide range of applications. This work investigated the use of a piezoelectric polymeric material, PVdF, in combination with 3D printing, to explore new strategies for the fabrication of smart materials with embedded functions, namely sensing. The motivation behind this research was to design and fabricate PVdF thin films that will be used to build pressure sensors with applications in active intelligent structures. In this work, 3D printed PVdF thin films with thickness values in the range of 250 to 350 μm were poled under high direct current electrical fields, which were varied from 0.4 to 12 MV/m and temperatures from 80 to 140 °C. Copper electrodes were applied, forming a standard capacitor layered structure, to facilitate poling and to collect piezoelectric output voltage. The poling process enabled the piezoelectric crystalline phase transition of printed PVdF films to transfer from the non-active a α-phase to the piezoelectric active β-phase and rearranged the dipole alignments of the β-phase. The efficiency of poling was evaluated through the piezoelectric constant calculated from measured calibration curves. These calibration curves demonstrated the PVdF sensing device have a positive linear correlation between mechanical input and voltage output. We found that a peak value in piezoelectric constant correlated with poling voltages and temperatures. The highest piezoelectric constant achieved through contact poling was 32.29 pC/N poled at 750 V and 120 °C, and temperature was deemed the most important factors to influence piezoelectric constant. We believe that the present work demonstrates a path towards fully 3D printed smart, functional materials.

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