(623d) A Novel Nano-Lithographic Pathway for Fabricating Anisotropic Nanoparticles of Different Shape and Composition

Performance of coatings is significantly dependent on the functional nanoparticles present in the system. The size, shape and the chemical nature of these nanoparticles modify the properties of the coatings. Anisotropic shapes, such as rod-like, star-shaped, prismatic, disk-shaped, cubical nanoparticles have been found to enhance the performance of coatings. This work has been inspired by the potential of developing a unique pathway to make different shaped anisotropic nanoparticles with a large flexibility in material choice.

The nano-lithographic method essentially followed a template directed approach using one of the most advanced thermal scanning probe lithographic instrument, NanoFrazor. This nanometer resolution mask writing tool was used to make a template in combination with dry reactive ion etching tool. The pattern shapes written by NanoFrazor were chosen according to the cross-sectional geometry of the final nanoparticles. The sizes of the nanoparticles had been controlled via optimisation of different parameters of NanoFrazor and dry etching step. Deposition of different metal/metal oxides by electron-beam evaporation method onto the templates allowed us to be flexible with choosing from a range of nano-materials according to the required functionality in the system. Dissolution of the sacrificial template lets the nanoparticles to be collected in a suitable solvent. The stability analysis of these nanoparticles made by the method will also be discussed along with relevant properties for using these particles in the coatings.