Name: Fabrication of the Capacitive Pressure Sensor
Uploaded: 2023-03-17T14:35:00
Description: Watch this Scientific Journal Video about Fabrication of the Capacitive Pressure Sensor at JoVE.com

The video demonstrates the fabrication process of a capacitive pressure sensor using platinum silicone foam and an interdigitated fringe effect design. It details mixing components, curing in a 3D mold, and the impact of varying ratios on sensitivity. A cyclic test confirms the sensor's durability and repeatability.

fabrication of the capacitive pressure sensor

Electrodos blandos basados en canales microfluídicos para la detección de presión capacitiva

Soft pressure sensors have been widely explored in applications such as pneumatic robotic grippers1, wearable electronics2, human-machine interface systems3, etc. In such applications, the sensory system requires flexibility and stretchability to ensure conformal contact with arbitrary curvilinear surfaces. Therefore, it requires all the essential components, including the substrate, the transducing element, and the electrode, to provide consistent functionality under extreme deformation conditions4. Moreover, to maintain high sensing performance, it is essential to keep the changes in the soft electrodes to the minimum level to avoid interference in the electrical sensing signals5.
As one of the core components in soft pressure sensors, stretchable electrodes capable of sustaining high stress and strain levels are crucial for the device to preserve stable conductive pathways and impedance characteristics6,7. Soft electrodes with excellent performance usually possess 1) high spatial resolution at the micrometer scale and 2) high stretchability with strong bonding to the substrate, and these are indispensable characteristics to enable highly integrated soft electronics in a wearable size8. Therefore, various strategies have been proposed recently to develop soft electrodes with the above properties, such as ink-jet printing, screen printing, spray printing, and transfer printing, etc.9. The ink-jet printing method6&#160;has been widely used due to its advantages of simple fabrication, no masking requirement, and a low amount of material waste, but it is hard to achieve high-resolution patterning due to limitations in terms of the ink viscosity. Screen printing10&#160;and spray printing11&#160;are simple and cost-effective patterning methods that require a shadow mask on the substrate. However, the operation of placing or removing the mask can reduce the clarity of the patterning. Although transfer printing4 has been reported to be a promising way to achieve high-resolution printing, this method suffers from a complicated procedure and a time-consuming printing process. Furthermore, most of the soft electrodes produced by these patterning methods have other disadvantages, such as delamination from the substrate.
Herein, we present a novel printing method for the rapid fabrication of cost-effective and high-resolution soft electrodes based on microfluidic channel configurations. Compared to other conventional fabrication methods, the proposed strategy utilizes elastic conductive polymer composites (ECPCs) as the conductive material and lithographically embossed microfluidic channels to pattern the electrode traces. The ECPCs slurry is prepared by the solvent evaporation method and consists of 7 wt.% carbon nanotubes (CNTs) well-dispersed in a polydimethylsiloxane (PDMS) matrix. By scraping the ECPCs slurry into the microfluidic channel, high-resolution electrodes defined by lithographic patterning can be produced. In addition, since the electrode is mainly based on PDMS, strong bonding is created at the interface between the ECPCs-based electrode and the PDMS substrate. Thus, the electrode can sustain a stretch level as high as the PDMS substrate. The experimental results confirm that the proposed stretchable electrode can respond linearly to axial strains up to 30% and exhibit excellent stability in a high-pressure range of 0-400 kPa, indicating the great potential of this method for fabricating soft electrodes in capacitive pressure sensors, which is also demonstrated in this work.

Autor destacado: Electrodos blandos basados en canales microfluídicos y su aplicación en la detección de presión capacitiva  

Electrodos blandos basados en canales microfluídicos y su aplicación en la detección de presión capacitiva

Our research really focuses on flexible and stretchable electronics for sensing applications, while trying to develop innovative materials and manufacturing precisely for flexible electronic systems. Flexible and stretchable electrodes are essential components in soft artificial sensory systems. Despite recent advances in flexible electronics, most electrodes are either restricted by the patterning resolution or the capability of inkjet printing, high-viscosity super-elastic materials.In this protocol, we have demonstrated a novel microfluidic channel-based printing method for stretchable electrodes. The conducting material of the electrode, the ECPC flooring, can be scraped into the microchannel, thus forming a conductive polymer that exhibits a stretchability as high as the PDMS substrate. Compared with the actions produced by existing fabrication methods, such as inkjet printing, scrape printing, spray printing, and transfer printing, the proposed microfluidic channel-based soft electrons have the advantages of a high printing resolution and high stretchability, with the strong binding to the substrate.The protocol presented in this research combines marriage of stretchable materials and microfluidic channels, enabling a low-cost and rapid application method for producing high-resolution, stretchable electrons for soft robotic tactile sensing applications.

Watch this Scientific Journal Video about Fabrication of the Capacitive Pressure Sensor at JoVE.com

Fabrication of the Capacitive Pressure Sensor  

Fabricación del sensor de presión capacitivo

Para ensamblar el sensor de presión capacitivo, fabrique el electrodo suave con un diseño de efecto de franja interdigitado. Mezcle los dos componentes de la espuma flexible de silicona de platino en proporciones de peso uno a uno y seis a uno, y revuelva rápidamente para preparar capas dieléctricas de espuma de silicona suave con dos tamaños de vertido. Vierte la mezcla en un molde impreso en 3D y cúbrela con una tabla con varios agujeros.Una vez que la mezcla esté curada, corte la espuma de silicona que entra por los orificios y retire la tabla. Finalmente, coloque la espuma dieléctrica preparada en la capa de electrodo blando interdigitado para finalizar la fabricación del sensor de presión. El dispositivo con un ancho de línea de 200 micrómetros tenía una mayor sensibilidad debido a un efecto de campo de franjas más fuerte.Y la espuma con una relación de peso más alta de la parte A a la Parte B también tenía una mayor sensibilidad que la espuma con una fracción de aire más baja. Una prueba cíclica reveló que el sensor capacitivo suave fabricado mantenía una alta repetibilidad a través de 1000 cargas de presión cíclicas.

Research

JoVE Journal

Engineering

Fabrication of the Capacitive Pressure Sensor

Microfluidic Channel-Based Soft Electrodes and Their Application in Capacitive Pressure Sensing

Flexible and stretchable electrodes are essential components in soft artificial sensory systems. Despite recent advances in flexible electronics, most ...