New technique manufactures wearables that work as a second skin

[OyaYansa]

A team of scientists from Harvard University in collaboration with the US Air Force Research Laboratory has created a new manufacturing technique for flexible electronic devices that can be placed in the body as a second skin. This breakthrough paves the way for the development of a new generation of much more practical, versatile and inexpensive wearables that can be used to obtain patient health data, track user movement, or perform other useful tasks.

The development of wearables has remained somewhat stagnant in recent years because it is complicated to integrate rigid electronic components into the flexible substrates that require this type of apparatus. Dressable electronics require that the devices have the ability to adapt to the shapes and movement of the body, but so far many of the components do not have this quality.

To end these problems and take a step forward in the development of wearables, these researchers have designed 3D hybrid printing, a new manufacturing technique that is capable of integrating soft conductive inks and matrix materials with rigid electronic components in a only flexible device.

"With this technique we can print the electronic sensor directly on the material, choose the electronic components digitally and print the conductive interconnections that complete the electronic circuits necessary to read the sensor data signal at one time," explains Alex Valentine, first author of the study.

The flexible conductive ink is composed of thermoplastic polyurethane (TPU), an elastic plastic that is mixed with silver scales. Both pure TPU inks and silver inks are printed to create the soft substrate of conductive devices and electrodes. The fact of printing the substrates in 3D gives the researchers a complete control of the conductive characteristics, allowing them to design the circuits in a personalized way to create devices of all sizes and shapes.

The soft sensors manufactured with these conductive materials are coupled with a programmable microcontroller to process the data obtained by the sensor. In addition, they integrate reading devices to translate the data, and other components, such as LED lights or resistors can also be added, applying a dot of TPU ink to adhere them.

In the video that you can find a little higher you can see the result of two prototypes made with this technique. One is a deformation sensor made on a textile base that records the times the arm is bent, and the second is a pressure sensor to integrate in the shoes that controls the footprints to draw heat maps.

This is just two examples, but the team says that the technique has the potential to manufacture all kinds of devices for many applications, such as medicine or sports, among many others.