Effect of the Nanoparticle Surface Termination on the Nanoparticle-Smectic Liquid Crystal Interaction: Order/Disorder Effect

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"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Technical summary: The proposal investigates how the surface termination of a nanoparticle affects the interaction between the liquid crystal and the nanoparticles. The systematic study of this system (liquid crystal/nanoparticle surface-termination/nanoparticle) is important for improved applications and biological applications. This system is interesting because the molecular spacing for the liquid crystals (3-4 nm) is comparable to the nanoparticles used. The nanoparticles can induce phase changes on the liquid crystals, depending on their surface or functionalization groups, and disorder the liquid crystal. The proposal will study the system as a function of 1. temperature; 2. liquid crystal film thickness; 3. particle concentration, both with and without and external magnetic field. These results will be compared with a phenomenological model that the P. I. has developed for the smectic-A phase ? nanoparticle ? surface coating system. The research has benefited from international collaborative work in the study of the heat capacitance of the system of nanoparticles/surface termination/liquid crystals as a function of temperature. The information obtained both from the heat capacitance and the x-ray study done in the present work will provide information on the disordering of the liquid crystal.Non-technical summary: Liquid crystals are important both for device and biological application. Liquid crystals are in TV?s, clocks and many other applications. They are also the phases of the walls of every living creature cell. The interaction of nanoparticles with liquid crystals is important to study since the molecular size of the liquid crystals is comparable to the nanoparticles. Inorganic nanoparticles are coated with an organic at their surface to improve their interaction with the organic liquid crystals and to identify specific cell walls in biological applications. This study investigates how the combination of the nanoparticle and their surface coating orders or disorders the liquid crystal, and can tell if the combination will be a disadvantage to applications or dangerous to living cells. Students working on this project will get an understanding of what has to be done to obtain better devices, and also what precautions have to be taking when using nanoparticles to interact with living creatures. The presentations done in professional and other meetings will inform the general public of these facts. Presentations to undergraduates and pre-college students will teach how liquid crystals appears in many aspects of their lives.