Nanoparticle inks for directed assembly of three-dimensional periodic structures

Colloidal inks, comprised of concentrated barium titanate nanoparticle gels, were directly assembled via a robotically controlled deposition technique. 3D periodic lattices were created through layer-by-layer patterning of parallel rods, whose periodicity far exceeded the dimension of the nanoparticle building blocks. The Figure shows a scanning electron microscopy image of a 3D periodic lattice (top view).