Additive Manufacturing of Controlled Anisotropic Materials via Electrically Assisted Nanocomposite Fabrication

University Of Southern California, Los Angeles CA

Investigators

Abstract

Additive manufacturing (AM) has emerged as a promising rapid manufacturing approach for a wide variety of industries. Current AM processes can fabricate a model with good control on its shape but not on its material properties. Most AM processes only enable the fabrication of structures with isotropic material properties (they are the same in all directions). This award supports fundamental research on a novel additive manufacturing process that can accurately create anisotropic material properties (properties that vary with direction). This is accomplished in a three-dimensional (3D) structure by dynamically controlling electric fields while fabricating each layer, which has the result of orienting the short fiber reinforcement (in the form of carbon nanotubes or metal flakes) in the polymer. The shape is achieved by changing the projection image for each layer. Hence, varying material properties can be achieved in the fabricated structure even when using a single type of nanocomposite. The research results will significantly expand the capability of AM processes to fabricate anisotropic materials with enhanced structural, thermal, and electric properties. Such capability will enable novel design and fabrication of impact resistant nanocomposites, thermo-metamaterials, and wearable sensors. The new manufacturing process will provide US companies with a competitive edge and can lead to innovations in aerospace, consumer electronics, defense, and medical industries. The research outcomes will be integrated into undergraduate/graduate course development, as well as outreach programs to increase minority participation. The research objective is to establish an electrically assisted mask-image-projection-based stereolithography (eMIP-SL) process that can build three-dimensional shapes using nanocomposites with controlled carbon nanotube (CNT) alignment for enhanced functional characteristics. Tasks on electrode design, nanocomposite preparation, CNT alignment control, and integration with projection-based stereolithography will be performed. The fundamental characteristic of the anisotropic mechanical/electrical/thermal properties of architectures with aligned carbon nanotubes will be studied including measuring the anisotropic mechanical properties, the electrical and thermal conductivities, and microstructure observation with optical/scanning electron microscopy. The fundamental mechanism for the anisotropic mechanical/electrical/thermal properties in the fabricated architectures will be studied as a function of the process parameters and resulting nano/microstructures. The research result will develop scientific and engineering knowledge on the eMIP-SL process for fabricating anisotropic multi-functional 3D structures using controlled properties of nanocomposites.