Dr. Antal Jakli
"Liquid Crystals Meet Water"
Figure 1. Cholesteric microlenses: (a) image of microlenses between circular polarizers; (b) number "50" imaged by the microlenses.
Thermotropic LCs used in LC display (LCD) TVs are made of organic molecules that do not mix with water and, therefore, interact only at 2D interfaces. Orientation of LC molecules is sensitive to particles or chemicals dispersed or dissolved in water. For example, LC molecules prefer to be parallel to the LC/water interface, but they turn away if surfactants, lipids, or NPs are added. This behavior is utilized in various LC-based biosensors1-3 and microfluidic devices and sensors.
Recently, we found that water also changes the shape of suspended LC droplets leading to self-assempled microlenses (Fig. 1) or bent films, and vice versa, LCs can influence the distribution of the chemicals in water.
In this project REU students will study LCs in different geometries and phases in aqueous environments. This project suits students with various backgrounds, such as physics, biology as well as chemistry, and will involve hands-on experiments with biologically relevant molecules (DNA, antibodies, etc.), LCs, interfacial phenomena, and various types of microscopy.
The tangible expectation of the project is to understand the role of chirality on shape formation of immiscible fluids.
- Brake, J. M., "Biomolecular Interactions at Phospholipid-Decorated Surfaces of Liquid Crystals." Science, 2003, 302 (5653), 2094-2097.
- McUmber, A. C.; Noonan, P. S.; Schwartz, D. K., "Surfactant-DNA Interactions at the Liquid Crystal-Aqueous Interface." Soft Matter, 2012, 8 (16), 4335.
- Popov, P.; Mann, E. K.; Jakli, A., "Accurate Optical Detection of Amphiphiles at Liquid Crystal-Water Interfaces." Phys. Rev. Applied, 2014, 1 (3), 034003.