- Researchers use liquid crystal elastomers to deform structures in three dimensions.
- It could lead to the development of solar panels that follow sunlight (like sunflower) for improved energy capture.
A variety of reconfigurable microstructures on biological surfaces enable living organisms to change their characteristics (like structural color and adhesion) in response to external stimuli. These biological creatures can exhibit predetermined deformation and cooperative movements based on stimuli, by combining their intrinsically encrypted chemical to externally applied fields.
For example, the setae on gecko’s sticky feet are made of special structures whose physical and chemical composition and ultra flexibility allow the lizard to easily grip ceiling and walls.
Scientists worldwide have been trying to replicate such change structures in the lab, using a range of materials such as liquid crystal elastomers (LCEs). However, they haven’t been able to deform the structure in three dimensions.
The problem with 1D and 2D deformation is you can’t move the structure throughout space to provide different shapes.
Now, researchers at Harvard University have developed a technique that solves this problem by controlling LCEs’ nanostructure with the magnetic field. It can produce microscopic 3D polymer shapes, which can be configured to shift in any direction in response to different stimuli.
LCEs can have light- and heat-responsive characteristics
The microstructures made of LCEs can be deformed into any shape in response to light, heat, and humidity. their reconfiguration is driven by their own material and chemical properties.
In this study, authors discovered that when LCEs are exposed to a magnetic field during the process of synthesization, all liquid crystalline elements within LCEs got aligned with the magnetic field. This molecular alignment retained even after the structure solidified.
Reference: PNAS | doi:10.1073/pnas.1811823115 | Harvard University
By altering the magnetic field direction, researchers were able to control how resulting LCE structures would deform in the presence of high temperatures. These structure didn’t lose their internally oriented shape while returning to the ambient temperature.
The researchers were able to develop LCEs capable of reconfiguring themselves in response to light. It all happens during a process called polymerization.
Once the structure is exposed to the light from a specific direction, the light facing side shrinks, causing the whole shape to bend toward the light. Such self-regulated motion allows structures to follow the light by continuously reorienting themselves.
Moreover, LCE microstructures can be produced with both light-and heat-responsive characteristics. Thus, a single-material structure can now have several response mechanisms.
Applications
The study could lead to the development of a range of useful instruments, including solar panels that follow sunlight (like sunflower) for better energy efficiency.
Read: Gold Nanoparticles Can Enhance the Solar Energy Storage
The technique can be used to encrypt the piece of information, which can only be disclosed when exposed to a particular temperature or adhesive substance. Overall, it can form the basis of multilevel encryption, autonomous source-following radios, and smart buildings and sensors.
