LIVING & LEARNING THROUGH LIQUID CRYSTALS BY MAIYA PACLEB
In the first week of March 2020, I submitted my application and proposal for summer research at the university with my mentor Dr. Eric Scharrer. What we didn’t know is that, just about a week later, our world was going to be altered completely. With our world facing the reality of the COVID-19 pandemic, there were doubts about what would constitute our everyday way of living. Soon, us students, along with our professors and faculty, were forced to face the hardships of virtual learning. Little did I know when I applied for summer research that I, as well as billions of people across the world, would have to rely upon the very things that I was studying—liquid crystals. So, what are liquid crystals (LCs), and why are we dependent on them? Think of your three phases of matter: solid, liquid, and gas. To transition between these phases of matter, you must overcome intermolecular interactions that exist between each molecule to push it into disorder. The amount of disorder ultimately determines the phase of matter. Between solid and liquid phases exists a discrete phase of matter that only some compounds can achieve, and these are classified as LCs. Because of this intermediate state of order LC molecules possess, they are pliable through application of an electric field. Through this malleable property, LC are able to interact with light differently to reflect visual images. The reorientation, or “switching,” of these molecules through electric manipulation and its interaction with light makes up what we know as Liquid Crystal Display (LCD) technology. You probably have seen this widely used in computers, phones, calculators, and televisions. Therefore, LCs makeup how we are able to see anything on the screen, and how we have continued to learn (as best we can) virtually through a pandemic.
ABOVE: Phase transition by temperature, going from solid phase to liquid crystal phase to the isotropic (liquid) phase However, this LC technology is far from perfect, and research is pushing to reach an optimized display method that would enhance quality and performance. LCD is primarily made up of single major-director containing LC compounds, called the uniaxial nematic (Nu) phase (1). This single major-director can be thought of as an axis that is maintained individually in each LC molecule, and further contributes to a large axis of orientation for a collective group of LC molecules. The nematic phase itself is valuable because there is no specific arrangement of the collective group of LC molecules, so the shape of the LC sample is pliable. Additionally, all of these LC molecules happen to be oriented simultaneously in the same direction. The Nu phase inherently provides properties that make it convenient to work with in display applications. Their disadvantage, simply put, is that these Nu compounds, both individually and collectively, have a large axis that only directs the compounds in one direction. To achieve reorientation or switching of this single director axis, it takes a lot more time and energy. So, what we really want is to attain a nematic phase that can switch quickly for display applications,
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