Scientists tried to replicate the microscopic hair-like structures that cover the pads of geckos’ notoriously sticky feet (whose chemical and physical composition and high flexibility allow the lizard to grip walls and ceilings with ease), with a variety of materials, including liquid crystal elastomers (LCEs), which are rubbery networks with attached liquid crystalline groups that dictate the directions in which the LCEs can move and stretch.
Now, a group of scientists from Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS) has harnessed magnetic fields to control the molecular structure of LCEs and create microscopic three-dimensional polymer shapes that can be programmed to move in any direction in response to multiple types of stimuli. The work could lead to the creation of a number of useful devices, including solar panels that turn to follow the sun for improved energy capture.
“What’s critical about this project is that we are able to control the molecular structure by aligning liquid crystals in an arbitrary direction in 3D space, allowing us to program nearly any shape into the geometry of the material itself,” said first author Yuxing Yao, who is a graduate student in the lab of Wyss Founding Core Faculty Member Joanna Aizenberg, Ph.D.
The microstructures created by Yao and Aizenberg’s team are made of LCEs cast into arbitrary shapes that can deform in response to heat, light, and humidity, and whose specific reconfiguration is controlled by their own chemical and material properties. One exciting application of these multiresponsive LCEs is the creation of solar panels covered with microstructures that turn to follow the sun as it moves across the sky like a sunflower, thus resulting in more efficient light capture.