Researchers achieved a high level of sensitivity in capacitive strain sensing for improved wireless monitoring of the strain on materials in a wide range of applications.
Monitoring the strains on materials is crucial for checking the safety of everything from buildings and bridges to ships and aircraft. Such sensors are also important for monitoring aspects in the field of health, sports performance and robotics.
Most strain sensors are composed of a material that can convert physical deformation into changes in electrical resistance or capacitance. The electrical signals coming out of the transducer have traditionally been carried to the detecting devices along wires, but more recently, wireless technology is bringing the obvious advantages of remote sensing. This is important to detect strains in difficult-to-reach locations, such as inbuilt structures, vehicles or inside the body.
However, existing strain sensors exhibit low sensitivity. Researchers from King Abdullah University of Science and Technology have solved this problem by introducing a special pattern of cracks into fragmented electrodes in a way that greatly increases the sensitivity of the electrical responses.
The developed sensor is essentially a capacitor with carefully fragmented electrodes made of carbon nanotube-containing paper. The electrical signals caused by different levels of strain generate signals that can be captured wirelessly by electromagnetic coupling.
The researchers now plan to embed it into readily deployable systems suitable for commercialization. 
The research appeared in the journal ACS Applied Materials and Sciences