In the ever-evolving landscape of technology, a newly discovered principle of the microworld can lead to the creation of shape-shifting robots of the future.
(Photo: Unsplash/ Kate Trysh)
Potential of Liquid Crystals
Liquid crystal is a thermodynamic stable phase with anisotropic properties without a 3D crystal lattice. It is a state of matter with properties that lie between those of conventional liquids and those of solid crystals.
Liquid crystals have become popular due to their ability to flow like liquids while maintaining a common orientation, like solids. These properties make them suitable for making LCD screens, biomedical imaging devices, and other tools that require precision light control.
Due to their unique and facile reconfigurability and tunability, liquid crystals provide a dynamic platform for developing advanced photonics and soft actuation systems. However, manipulating the alignment of liquid crystals in three dimensions has been an expensive and intricate process until now. Achieving liquid crystal alignment with precise spatial patterns is crucial to developing directed colloidal assembly, programmable origami, electro-optical devices, and controlling active matter.
Manipulating Molecular Properties of Liquid Crystals
At Johns Hopkins University, experts unveiled a revolutionary discovery involving the manipulation of liquid crystals with light exposure. The results of their study, "Spatial Photo-Patterning of Nematic Liquid Crystal Pretilt and its Application in Fabricating Flat Gradient-Index Lenses," promise an avenue for future applications.
Led by doctoral researcher Alvin Modin, the research team aims to develop an affordable approach to creating three-dimensional liquid crystal molecules. They believe this can be achieved even with essential tools like microscopes and lenses.
In this study, the scientists manipulated light exposures on a photosensitive material deposited on glass and successfully controlled the 3D orientation of liquid crystals. The experiment allowed the researchers to shine polarized and unpolarized light on the liquid crystals through a microscope.
The team discovered that in polarized light, light waves oscillate in particular directions rather than moving randomly in all directions. This pattern is characteristic of unpolarized light. This discovery allowed the researchers to create a microscopic lens of liquid crystals that can focus light depending on the polarization of light that shines through it.
If a scientist wanted to make an arbitrary 3D shape, such as an arm or a gripper, they would have to align the liquid crystals to restructure spontaneously into those shapes when subjected to a stimulus.
Their finding opens up possibilities for programmable tools that can adapt to stimuli. For instance, rubber-like robots capable of handling complex objects or camera lenses that automatically adjust focus in various lighting conditions can be made.
It also provides opportunities for laboratories and manufacturers worldwide to harness the potential of liquid crystals in creating the next generation of robots and cameras. Using the newly discovered method, any industrial laboratory with a microscope and a set of lenses can arrange the alignment of liquid crystals in any pattern they want.
Modin and his colleagues are working towards a patent application for their discovery. They also plan to perform further tests with various liquid crystal molecules and solidified polymers.
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