Close-fitting clothing can be used as an electrode, and Japan has developed wearable new materials.

On February 21st, the business agency put on an electrode for monitoring ECG and pulse as soon as wearing a sweatshirt. Such a product has already been developed, which is jointly developed by Nippon Telegraph and Telephone Corporation (NTT), NTT DoCoMo and Toray. " Apparel for monitoring vital signs" (Figure 1). Since the electrodes are already implanted in the garment, there is no need to attach a metal electrode to the surface of the body. Signs can be easily monitored during exercise and sleep. The product can also be washed with water. According to NTT, “Washing the washing net can be washed more than 30 times. If it is hand-washed, it can maintain conductivity even after 50 to 60 washings.”

To obtain the physical information, it is necessary to connect a small dedicated device to the metal button located near the left shoulder of the clothing for monitoring the vital signs. The device has built-in continuous monitoring of heart rate and ECG waveforms, and has the function of transmitting Bluetooth to a smartphone in short-range wireless communication.

In 2014, NTT DoCoMo plans to provide services that link clothing for physical information monitoring with smartphones.

Encapsulating conductive materials in nanofibers

The cloth "hitoe" made of a conductive polymer "PEDOTPSS" coated on a nanofiber cloth is used to make a sweatshirt, and the body information such as heart rate and electrocardiogram waveform can be monitored by wearing it.

The reason why the clothing for monitoring vital signs information can be realized is that the conductive functional material "hitoe" has been developed. Hitoe's basic technology is the conductive polymer "PEDOT-PSS" that NTT has been developing. PEDOT-PSS not only has softness, hydrophilicity, strength, but also biocompatibility, so it does not feel uncomfortable even if it is close to the skin. On the other hand, since it has hydrophilicity, it has a disadvantage that it is easy to fall off after washing.

Toray's nanofibers solve this problem by immersing PEDOT-PSS in a fabric made of polyethylene terephthalate (PET) fibers (PET nanofibers) with a diameter of only 700 nm. As a result, PEDOTPSS remains in the fiber and the washing resistance is improved. It is said that the diameter of the PET fiber used in ordinary clothes is about 15 μm, so that PEDOT-PSS remains on the surface of the fiber and is therefore not resistant to washing. In addition, by using PET nanofibers, the contact area of ​​the fabric with the skin is larger than when using ordinary fibers, so reliable monitoring results can be obtained.

It is said that the clothing optimizes the position of the electrodes for monitoring heart rate and electrocardiogram. If the electrodes are replaced with other positions, the electromyogram and brain waves can also be monitored. (Author: in truth, the Nikkei online technology feeds!)