In recent years there have been several advances with electronic skin technology. Skins are being developed for medical applications and for robots, with the aim of teaching robots with artificial intelligence about sensing touch.
The quest for artificial skin has inspired innovations in materials to imitate skin’s unique characteristics, including mechanical durability and stretchability, biodegradability, together with the ability to measure a diversity of complex sensations across large areas. One suitable material is graphene, with its high transparency, rapid carrier transport, flexibility and large specific surface area.
A new advance with electronic skin, suitable for prosthetics used to assist people who have lost limbs, is building in a mechanism to indicate potential harm. At present prosthetics do not respond to a harmful blow, which carries the risk of damaging the prosthetic or even another part of the human body.
This development has been inspired by jellyfish, in that the skin glows when subject to pressure calibrated to a level where the applied pressure could be sufficient to cause injury. High pressures can also cause damage to the electronic and mechanical parts of the prosthetic.
A weakness hindering the development of electronic sensitive skin is a phenomenon that occurs whereby as pressure increases the sensitivity of the electronic skin decreases. This has been overcome by Dr. Bin Hu from Huazhong University of Science and Technology.
Dr. Hu drew inspiration from the Atolla jellyfish. The Atolla jellyfish (Coronate medusa) is a species of deep sea crown jellyfish. The jellyfish has 22 tentacles and one long trailing hypertrophied tentacle, to facilitate prey capture. The jellyfish has a deep red color, which makes it almost invisible. When threatened, however, the creature is capable of bioluminescence, causing it to flash in order to distract and frighten the attacker.
The important features of the jellyfish are revealed in this short video:
For the development, Dr. Hu linked electric and optical systems in a novel electronic skin. This enables the detection of both slight and high-force pressures. For this his research team embedded two layers of stretchy, poly-dimethysiloxane film with silver nanowires.
The layers produce an electrical signal when subject to slight pressures, including those gentle enough to be created by a breeze or contact with a leaf. Locked in between the silver nanowire electrodes is the poly-dimethysiloxane film embedded with phosphors. This layer glows with growing intensity as the physical force increases.
It is hoped this development will be used in both prosthetics and robotics to more closely mimic the range of pressures the human skin detects.
The new research has been reported to the journal ACS Applied Materials & Interfaces. The research paper is titled “Dual-Mode Electronic Skin with Integrated Tactile Sensing and Visualized Injury Warning.”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we looked at a “molecular pencil sharpener.” This is a device that uses chemicals to generate a “warhead” of proteins that increase in toxicity once “sharpened”. The research has focused on killing the Escherichia coli bacterium.
The week before we profiled how University of Michigan researchers devised new means for enhancing the security of voice activated software. The aim was to eliminate the vulnerabilities associated with voice authentication.
