Artificial active

Researchers create self-propelled artificial eyelashes

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have successfully developed a programmable, self-propelled artificial eyelash. The new breakthrough comes after years of scientists trying to design tiny artificial eyelashes for miniature robotic systems. Artificial eyelashes could help these robotic systems perform highly complex movements like bending, twisting and inverting.

The research has been published in Nature.

Construction of Microstructures

Traditionally, the construction of microstructures requires multi-step manufacturing processes and various stimuli in order to create complex movements, which has limited their large-scale applications.

The newly developed micron-scale structures could be used for many applications, including soft robotics, biocompatible medical devices, and dynamic information encryption.

Joanna Aizenberg is the Army Smith Berylson Professor of Materials Science and Professor of Chemistry and Chemical Biology at SEAS. She is also the lead author of the article.

“Innovations in self-regulating adaptive materials capable of a diverse set of programmed movements represent a very active field, which is being tackled by interdisciplinary teams of scientists and engineers,” said Aizenberg. “Advances in this area can have a significant impact on how we design materials and devices for a variety of applications, including robotics, medicine, and information technology.”

Allow the structure to reconfigure and propel itself

While previous research involved complex multicomponent materials to realize the structural elements of these systems, the new team designed a microstructure pillar made of a single material. This unique material is a light-sensitive liquid crystal elastomer, which allows the building blocks to realign and the structure to change shape when light strikes the microstructure.

When the shape change occurs, the first thing that happens is that where the light strikes becomes transparent, allowing the light to penetrate deeper into the material and cause even more deformation. After that, the material deforms and the shape changes, which means that a new point on the pillar is exposed to light and also changes shape.

This process allows the microstructure to propel itself through a cycle of motion.

Shucong Li is a graduate student in the Department of Chemistry and Chemical Biology at Harvard, as well as co-first author of the paper.

“This internal and external feedback loop gives us a self-regulating material. Once you turn on the light, it does all its work,” Li said.

The material then returns to its original shape when the light goes out. Because the material can twist and change motion with its shape, the simplest structures can be reconfigured and adjusted with endless possibilities.

Michael M. Lurch is a postdoctoral researcher at the Aizenberg Laboratory and co-first author of the paper.

“We showed that we could program the choreography of this dynamic dance by adapting a range of parameters, including illumination angle, light intensity, molecular alignment, microstructure geometry, temperature and intervals. and the duration of irradiation,” Lerch said.

The team also demonstrated how the pillars interact with each other as part of a network.

“When these pillars are grouped together, they interact in very complex ways because each warping pillar casts a shadow on its neighbor, which changes throughout the warping process,” Li said. shadow-mediated dynamically change and interact with each other could be useful for applications such as dynamic information encryption.”

“The vast design space for individual and collective movement is potentially transformative for soft robotics, micro-walkers, sensors, and robust information encryption systems,” Aizenberg added.

The research also included co-authors James T. Waters, Bolei Deng, Reese S. Martens, Yuxing Yao, Do Yoon Kim, Katia Bertoldi, Alison Grinthal, and Anna C. Balazs.