A method of forming an array of pointed structures comprises depositing a ferrofluid on a substrate, applying a magnetic field to the ferrofluid to generate an array of surface protrusions, and solidifying the surface protrusions to form the array of pointed structures. The pointed structures may have a tip radius ranging from approximately 10 nm to approximately 25 μm. Solidifying the surface protrusions may be carried out at a temperature ranging from approximately 10 degrees C. to approximately 30 degrees C.