In, Graphene: A new material for electronics, Part 2, of this blog series, I focused on the possible utilizations of graphene as building material for innovative applications in electronics ranging from hybrid systems for light-on-chip applications to LEDs for an unprecedented illumination effect in the displays for consumer electronics devices (smartphone, tablets, etc.) Furthermore, the physical properties of graphene material are being further explored by companies working in the semiconductor environment. The result of these studies is an unbounded scenario of possibilities for graphene electronics:
“Graphene can be used as a coating to improve current touch screens for phones and tablets. It can also be used to make the circuitry for our computers making them incredibly fast. These are just two examples of how graphene can enhance today's devices. Graphene can also spark the next-generation of electronics.” (Source: Manchester 1824, The University of Manchester)
The key factor that can make the difference between graphene and the other materials is its exceptional thickness that is ideal in realizing printed electronics circuits that are perfect for wearable electronics technology:
”Based on innovative silver and dielectric inks, DuPont’s array of flexible materials for wearable technology offer a host of benefits, including exceptional stretch performance and washability. They’re resistant to detergents and can be washed in a regular washing machine. These features enable greater freedom for designers, enhanced wearer comfort, and cost savings for high-volume manufactured wearables. Applications for wearable electronics and smart fabrics include health monitoring, communication, and Organic Light Emitting Diode (OLED) displays.” (Source: DuPont USA). (See Figure 1)
Possible applications for printed electronics products (Source: DuPont/Wearable electronics)
What would be the advantages of a wearable electronic device on the human health? An interesting answer to this question is represented by the works of National Institute of Standards and Technology(NIST) Physical Measurement Laboratory (PML) in collaboration with Tufts University:
“NIST's Physical Measurement Laboratory (PML) is currently collaborating with Tufts University's School of Medicine to develop just such a model, a blood pressure wrist “phantom” – essentially a fake arm that mimics the mechanical properties of blood pulsing through an artery surrounded by human tissue.
The materials were carefully selected to match the properties of skin, soft tissues, bone, and artery walls, the researchers say. But unlike actual live human tissue, the phantom can easily have sensors running through it, measuring the pressure changes that occur each time water is pumped through the tube. “(Source: Wearable Technology Insights)
The substrate thickness and flexibility is an important feature in realizing a wearable sensor able to measure blood pressure, thus graphene material has a good potential to be a perfect fit for these types of applications. (See Figure 2)
The development of a wearable fitness device to continuously monitor blood pressure (Source: wearabletechnologyinsights.com)
Wearable sensors built using graphene are a very interesting application of electronics in human motion and the scientific community is working to develop such types of sensors:
“Sensing strain of soft materials in small scale has attracted increasing attention. In this work, graphene woven fabrics (GWFs) are explored for highly sensitive sensing. A flexible and wearable strain sensor is assembled by adhering the GWFs on polymer and medical tape composite film. The sensor exhibits the following features: ultra-light, relatively good sensitivity, high reversibility, superior physical robustness, easy fabrication, ease to follow human skin deformation, and so on. Some weak human motions are chosen to test the notable resistance change, including hand clenching, phonation, expression change, blink, breath, and pulse. Because of the distinctive features of high sensitivity and reversible extensibility, the GWFs based piezoresistive sensors have wide potential applications in fields of the displays, robotics, fatigue detection, body monitoring, and so forth.” (Source: “Wearable and Highly Sensitive Graphene Strain Sensors for Human Motion Monitoring”)
Graphene is an ideal substrate for wearable sensor ICs because of its exceptional physical properties of flexibility and thickness. Do you think that this type of material will be further utilized for wearable applications? Do you think that wearable ICs could be used for many other types of monitoring purposes in human physical activity?