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I’ve been interested in the Interact Lab for many years as I saw news stories, even in Japan, about their novel and futuristic displays, such as 3D fog displays and mid-air haptic interfaces known as Ultrahaptics.
After joining the university following work at the Microsoft Applied Sciences Group in the US and Utsunomiya University in Japan, I first used my cross-disciplinary background to research a wide variety of physical sciences such as optics, acoustics, materials science and fluid dynamics to find interesting physical phenomena and inspiration for new ground-breaking displays “beyond common sense”. After many trial-and-error attempts with my colleagues, we finally made some unique inventions such as our recent liquid metal morphing system.
Liquid metal has the unique property of dynamically changing its surface tension in reaction to the polarity and magnitude of applied voltage. By charging liquid metal positive or negative with a voltage-controlled electrode, we can control its shape: droplets or marbles for negative, and flat or wet for positive.
By controlling the voltage and distribution of electrode arrays, we can control the speed and shape of the liquid metal’s deformation. Tracking the position and shape of liquid metal and electrode array with a live web camera, our software automatically optimises distribution of voltages across electrode arrays and draws a desired physical shape with the metal.
Transformers
The shape-shifting liquid metal opens new possibilities in tangible shape-changing physical displays and reconfigurable electronic circuits. The most interesting application is shape-shifting, reconfigurable circuits for soft robotics.
Liquid metal is highly conductive, similar to ink used for printed flexible circuits. Unlike conventional conductive ink, however, liquid metal maintains high conductivity at liquid state and is more flexible, extensible and adaptive to deformation.
(Credit: iStock)
By embedding our shape-changing liquid metals in a soft body, we could further enable soft robotics to change their internal circuits on demand to meet tasks. For instance, by forming the shape of RF antenna, the metal could work to transmit or receive signals.
We could also potentially create the shapes of electronic switches with the metal, letting us control the connection of multiple components like LEDs, sensors and motors without hardwiring. The reshaping process could also be useful for soft robots to self-heal broken circuits.
Liquid revolution
There is an interesting prior study about using liquid metal as micro-scale pump actuators, so perhaps our technology could replace solid electronic motors with formless actuators, helping create more flexible and transformable soft robotics.
The process could have many other uses. As the substance shifts phase between liquid and solid at room temperature, we could potentially make a new type of 3D metal printer which enables more rapid prototyping than conventional approaches. Spatial control of stiffness in the liquid metal by temperature could also lead to unique haptic devices for virtual-reality applications or mobile-phone touch interfaces.
Our study of shape-changing liquid metal has just started and there are many improvements we can expect to achieve. Our current prototype is made of 49 electrodes to deform the shape of liquid metal and controls only a few liquid metal attraction points. Hence, we can only draw a simple outline of a primitive image such as an alphabet letter or a heart shape at the moment.
Our next goal is to improve spatial resolution by fabricating more arrays of electrodes in a high density and control multiple electrodes’ voltage simultaneously to render and animate more complex images, such as realistic human faces. Fine-grain control of a multiple electrode array could also control multiple liquid metals independently on the same surface.
We are excited to see how our study will open new possibilities in liquid metal research and application, and lead to a revolution in new displays, electronics and soft robotics.
Content published by Professional Engineering does not necessarily reflect the views of the Institution of Mechanical Engineers