Researchers 3D Print Electrically Conductive Strain Sensors - 3DPrint.com
For those who are unfamiliar with the technology, a strain sensor is a type of data collection device which can detect electrical currents, and thus the strain on an object. Such a sensor takes advantage of the fact that the electrical conductivity of an object changes as its geometry changes. A typical sensor usually sits in a coiled state when relaxed. When the object the sensor is embedded in stretches or strains, that sensor is also stretched. As it’s stretched it becomes narrower and longer, leading to a state in which its electrical resistance increases. On the contrary, if that sensor is compressed, the opposite will occur. The data captured by measuring these changes in electrical resistance allows for a measurement of strain.
In order to embed sensors into a device, the team of researchers developed a multi component materials system. The system used is composed of materials which are elastic, and chemically compatible with one another. They include a viscoelastic ink, a reservoir, and a filler fluid. The reservoir was able to facilitate a patterning of the ink, without permitting it to break up, as the nozzle printed the conductive ink into it. The filler fluid they used once the ink is printed into the reservoir was a modified, commercially available silicone elastomer called Ecoflex 00-30. The same material was also used for the reservoir itself. The configuration of the system can be seen in figure ‘a’ below. Figure ‘b’ shows a planar array of soft strain sensors which have been 3D printed.