Hierarchical Nanolayered Polymer/nanoparticle Composites via 3D Printing*

Nanoparticle preferential alignment and oriented structures improve functional and structural properties in composites compared to those with random counterparts. Traditionally used techniques such as drop-casting, chemically modified surfaces, and external fields have been used for self-assembly, but it has several disadvantages. Thus, there is a need to develop a new approach for generating hierarchical nanoparticle structures. This research combines advanced 3D printing and evaporation-induced nanoparticles assembly for layer-by-layer deposition of 1D and 2D nanoparticles. The 1D and 2D nanoparticles were deposited onto the 3D printed substrate with microchannels via solution deposition technique. The nanoparticles trapped by microchannels experiences microfluidic forces, which lead to site-specific deposition and alignment of nanoparticles. The fabricated polymer/nanoparticle composite film showed different deposition morphologies like straight, wavy, and randomly oriented films. Furthermore, the influence of nanoparticle deposition morphology on functional properties was investigated. This novel technique shows the potential to scale up microelectronics production by 3D printing of electronic structures like interdigitated devices, FET, and circuits.