Electronic skin : flexible and stretchable organic electro-mechanical sensors for robotics, wearable electronics and health monitoring
Abstract/Contents
- Abstract
- The natural biological skin's sensor performance presents tremendous challenges to emulate on artificial, electronic systems. High sensitivity, stretchability, and self-repair are salient characteristics of natural skin that, if re-created on artificial electronic skins can empower robotics, wearable devices, and biomedical applications. Organic materials that are inherently soft, flexible, or elastic are useful starting materials to use for artificial electronic skins. In this thesis, we explore the use of soft, elastic rubber as building blocks for force/pressure sensors. In particular, we developed highly sensitive capacitive pressure sensors, and in combination with organic semiconductors, created the first pressure-sensitive organic field effect transistors with unprecedented sensitivity and speed. Our sensors can detect static pressures as small as 3 Pa with milisecond response times. We performed finite element modeling to understand how the shapes of the elastic rubber impacts mechanical sensitivity, and describe the use of soft lithography techniques as a scalable means of manufacturing such elastic shapes. We further developed such organic field effect pressure sensors on flexible substrates that can be integrated onto smart bandages to monitor the human pulse when placed on the radial artery near the wrist. To enable stretchable pressure sensors, we developed a technique to create surface buckling of carbon nanotubes. The buckled nanotube films are highly stretchable and transparent, achieving greater than 2,200 S/cm and stretchable up to 150% strains. In addition, we demonstrate the first repeatably self-healing electronic skin using a supramolecular organic-inorganic composite. We developed the self-healing material using a composite approach, and achieved a conductivity as high as 40 S/cm. The composite material is mechanically flexible, and is capable of sensing tactile and flexion forces. Lastly, we propose using organic transistors to build oscillatory circuits that respond to pressure in a similar fashion to that of biological touch receptors. We call our system Digital Tactile Sensors (DiTACTS). The DiTACT prototype sensor generates a frequency of about 0 - 200 Hz, with the frequency being proportional to the pressure applied. Thus, DiTACTS encodes pressure information using frequency encoding, similar to that of slow-adapting biological touch receptors.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Tee, Chee Keong |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Bao, Zhenan |
| Thesis advisor | Bao, Zhenan |
| Thesis advisor | Nishi, Yoshio, 1940- |
| Thesis advisor | Poon, Ada Shuk Yan |
| Advisor | Nishi, Yoshio, 1940- |
| Advisor | Poon, Ada Shuk Yan |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Chee Keong Tee. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Chee Keong Tee
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