Liquid Crystalline Assemblies of Inorganic Nanorods
Shanthi Murali1, Khristine Pizarro1, Kyle Taylor1, and Virginia A. Davis2. (1) Chemical Engineering, Auburn University, 212,Ross Hall, Auburn, AL 36849, (2) Department of Chemical Engineering, Auburn University, Auburn, AL 36849
The recent development of facile routes for the production of inorganic nanorods, nanowires, and nanowhiskers has resulted in an array of materials with intriguing optical, electronic, magnetic and structural properties. However, the production of many functional materials requires aligning nanorods on the micro- to macro- scales. The combination orientational self-assembly of anisotropic materials into liquid crystalline phases and shear alignment is a well established means to produce high performance polymeric materials such as bullet-proof vests and liquid crystalline displays. The general foundation for the self-assembly of anisotropic particles in solution dates back to Onsager (1949), understanding the liquid crystalline phase behavior of nanorod dispersions is a nascent field formed by the intersection of nanotechnology, liquid crystalline science and colloid science. We report on the assembly of silver and silicon nitride nanorods into liquid crystalline phases and aligned films. Optical microscopy, RAMAN spectroscopy, Differential Scanning Calorimetry and Rheological characterizations were used to characterize the dispersions and films. This work represents a step forward in developing a fundamental understanding about the impacts of nanorod concentration, nanorod aspect ratio, and nanorod-nanorod and nanorod-solvent interactions on liquid crystalline phase behavior.