New progress made in the preparation of flexible strain sensors for solids institutes of the Chinese Academy of Sciences

[China Instrument Network Instrument Development] In the near future, the Institute's research group Guang Tao made new progress in the preparation of flexible strain sensors and the study of force sensitivity characteristics.

Polyaniline digital camera photos

The relevant research results are published in the magazine of Organic Electronics (Organic Electronics, 47 (2017) 51-56) titled "Flexible strain sensor with high performance based on PANI/PDMS films".

With the rapid development of science and technology, sensors have been widely used in fields such as biomedical detection, intelligent robots, flexible displays, wearable devices, etc. These fields often require the sensor to have a bendable and stretchable characteristic, which can satisfy the attachment. Demand on various irregular surfaces. In addition, a good strain sensor should also have high sensitivity (GF) and low resistance values. GF too low means that the sensor is prone to signal errors due to the small amount of change when detecting strain, and too large a resistance value means that a high-precision and expensive test instrument is required.

Currently, there are two types of sensitive sensors for flexible strain sensors: one is a sensor that uses conductive materials such as silver, carbon tubes, and graphene as strain-sensitive materials. Such sensors have low resistance values, and GF is also low; One is a sensor using a semiconductor material as a strain-sensitive material. This type of sensor has a high GF, but its resistance is also high. Both types of sensors are subject to certain restrictions in commercial applications. Therefore, designing a flexible sensor with low resistance and high GF is imminent.

Polyaniline (PANI) is a conductive polymer material. The conductivity after doping with protonic acid is between the metal and the semiconductor, and can change with the acid doping concentration. Therefore, the polyaniline and the elastic material polydimethyl PDMS bonding is expected to achieve low resistance and high GF requirements. Based on this, Dr. Gong Xinxin of the research group and Fang Ming, associate researcher used PANI as the conductive layer, PDMS as the elastic layer to prepare the PANI/PDMS composite film flexible strain sensor, and studied the performance of the sensor. The experimental results show that the PANI/PDMS composite film sensor has a certain flexibility, can stretch to 50% of the strain, the highest GF value can reach 54, much higher than other materials constructed flexible strain sensor, and has excellent cycle stability , It has potential application prospects in monitoring human activities.

The above work has been funded by the National Major Scientific Research Project and several National Natural Science Foundation projects.

(Original Title: New Progress Made in the Study of Flexible Strain Sensors for Solids)