The largest sheet of sensors that Bao's group has produced to date measures about seven centimeters on a side. The sheet exhibited a great deal of flexibility, indicating it should perform well when wrapped around a surface mimicking the curvature of something such as a human hand or the sharp angles of a robotic arm.
Bao said that molding the rubber in different shapes yields sensors that are responsive to different ranges of pressure. "It's the same as for human skin, which has a whole range of sensitivities," she said. "Fingertips are the most sensitive, while the elbow is quite insensitive."
The sensors have from several hundred thousand up to 25 million pyramids per square centimeter. Under magnification, the array of tiny structures looks like the product of an ancient Egyptian micro-civilization obsessed with order and gone mad with productivity.
But that density allows the sensors to perceive pressures "in the range of a very, very gentle touch," Bao said. By altering the configuration of the microstructure or the density of the sensors, she thinks the sensor can be refined to detect subtleties in the shape of an object.
"If we can make this in higher resolution, then potentially we should be able to have the image on a coin read by the sensor," she said. A robotic hand covered with the electronic skin could feel a surface and know rough from smooth.
That degree of sensitivity could make the sensors useful in a broad range of medical applications, including robotic surgery, Bao said. In addition, using bandages equipped with the sensors could aid in healing of wou
|Contact: Louis Bergeron|