Researchers develop arrays of tiny crystals that deliver efficient wireless energy

Imagine controlling a drone from the ground that gets its power from a laser beam, so it doesn't need to have a big onboard battery.

That is the goal of a team of researchers from the Hayward Research Group at the University of Colorado, Boulder.

Researchers from the Department of Chemical and Biological Engineering have created a novel, durable photomechanical material that can convert light energy into mechanical work without the use of heat or electricity, opening up novel possibilities for energy-efficient, wireless, and remotely controlled systems. A few of the many sectors it has the potential to impact include robotics, aircraft, and biomedical devices.

Professor Ryan Hayward remarked, "We cut out the middle man, so to speak, and take light energy and turn it directly into mechanical deformation."

In a research released on July 27 in Nature Materials, Hayward and his team describe the novel material.

The substance is made up of microscopic organic crystals that, when exposed to light, begin to bend and lift objects. Based on the findings, it is possible to wirelessly operate or power robots or vehicles using these photomechanical materials, which present a prospective replacement for electrically connected actuators. Additionally, increasing the effectiveness of direct light-to-work conversion gives the chance to do away with bulky thermal management systems and hefty electrical components.

The study contrasts with earlier efforts using fragile crystalline materials that underwent a photochemical reaction to alter form, but frequently fractured when exposed to light and were difficult to convert into practical actuators.

The fact that these new actuators are far superior to the ones we previously used is intriguing. They are fast to react, durable, and capable of lifting big objects.

The novel method developed at Hayward's Lab makes use of arrays of tiny organic crystals embedded in a sponge-like polymer substance. The crystals become substantially more durable and capable of producing more energy when exposed to light as they develop inside the polymer's micron-sized holes. They are extremely adaptable for a variety of applications because to their flexibility and simplicity of shape.

Due to their orientation, crystals may bend or raise items when they are exposed to light. When a load is connected and the material changes form, it acts as a motor or an actuator to move the weight. Greater than themselves items can be moved by the crystals. For instance, the.02 mg strip of crystals effectively lifts a 20 mg nylon ball, lifting 1,000 times its own mass. This is seen in the figure above.

Lead author Wenwen Xu, a former postdoctoral researcher in Hayward's group (now at the Sichuan University-Pittsburgh Institute), and Hantao Zhou, a graduate student in Hayward's group (now with Western Digital), are both CU Boulder researchers.Collaborators from Stanford University and the University of California, Riverside were also participating in the project.

The team wants to improve control over the mobility of the material in the future. Currently, only bending and unbending may change a material from a flat state to a curved state. Their goal is to maximize the quantity of mechanical energy generated relative to the light energy intake in order to maximize efficiency.

Before these materials can truly compete with current actuators, Hayward notes that there is further work to be done, especially in terms of efficiency. "However, this study is a significant step in the right direction and provides us with a roadmap for how we might be able to get there in the coming years," the author said.