(384c) Selective Nanoparticle Orientation for Polymer Composites Via Hybrid Manufacturing

Nanoparticle alignment can benefit the controllable light transmittance, targeted drug delivery, gaseous or liquid separation/purification, localized heat transfer, and, the mechanical reinforcement in composites. Self-assembly, electrical or magnetic fields, and mechanical forces have been used to achieve the nanoparticle arrangements. However, it is hard to reach large manufacturing speeds and high fabrication resolutions. Our approach using 3d printing and template effects allows producing scalable preparation of samples on which nanoparticle orientations can be well controlled. The in-house designed 3d printing had the developed surface topologies with a series of patterns such as line grooves or dot wells manufactured on substrates. Both resin-based and filament-based additive manufacturing mechanisms were included in the manufacturing process. Upon dispersed in suitable solvents, the nanoparticles adhered to the printed surface along the liquid-air-solid contact lines. The drying thermodynamics and the confinement effects from the template arranged the nanoparticles with different morphologies. Additive layers were duplicated on top of each polymer/nanoparticle pair, and results of the nanoparticle alignment were examined. Both thermoplastic and thermoset polymers were used as substrates, and surface tension influences on nanoparticle arrangements were also correlated. The orientation of nanoparticles and the relationships to the processing conditions were studied by polarized optical microscopy (POM), atomic force microscopy (AFM), x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical properties like static modulus, strength and toughness were measured for the layered composites.