A team of researchers from Technion – Israel Institute of Technology led by Professor Hossam Haick have found a way to develop flexible sensors capable of sensing touch and detecting variations in temperature and humidity. These properties make this sensor an ideal candidate for use in artificial electronic skins (e-skin).
The new sensor is developed by making use of tiny gold particles along with a type of resin. The sensors currently used in e-skin systems are only capable of detecting touch, while this new sensor is a bit closer to the sensory functions of real skin, by being capable of detecting three different kinds of data simultaneously. Moreover, this new flexible sensor is over 10 times more sensitive than the conventional touch sensors used in e-skins.
The new sensor is made of monolayer-capped gold nanoparticles of 5-8 nanometers in diameter. These nanoparticles are surrounded by connector molecules known as ligands. These nanoparticles were laid on top of a polyethylene terephthalate (PET) substrate and the resulting compound was found to conduct electricity differently, depending on how the substrate was bent. This phenomenon is attributed to changes in the distance between particles, resulting in changes in the rate at which electrons pass between them. This property also allows the sensor to detect pressures ranging anywhere from ten of milligrams to tens of grams. The sensor, being very stable can be attached to any surface shape, while maintaining its functions.
Now it is up to the researchers to develop methods to effectively attach this e-skin to prosthetics, so that amputees may once again be able to feel changes in their environment. These sensors can be easily customized by varying the thickness or composition of the substrate to modify its sensitivity. With suitable modifications, these sensors can also be used to monitor strain on concrete structures, detecting cracks in the engine etc.
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