3-D Nano-Fiber Manufacturing by Controlled Pulling of Liquid Polymers using Nano-Probes

In-addition to the applications of imaging and characterization, proximal probes are proposed to be used as three-dimensional (3-D) nano-scale manufacturing tools in this paper. Commercially available Atomic Force Microscope (AFM) systems are mainly limited to 1-D or 2-D manipulation tasks, and advanced 3-D nano-manufacturing applications are not possible. Therefore, this paper proposes 3-D nano-scale manipulation of liquid polymer nano-fibers by using precise positioning and temperature control. AFM nano-probe is used to pull or extrude thermoset or thermoplastic polymers precisely to fabricate 3-D polymer nano-fiber structures. A liquid SU-8 polymer structure bridge between the probe tip and a substrate is held when pulling the probe from the surface with controlled speed and position. For thermoset polymer, by heating the substrate and moving the AFM probe tip in a precise 3-D trajectory, the liquid fiber is cured in real-time while a predetermined 3-D shape is constructed. To model the curing of thermoset resins a three dimensional transient heat transfer scheme using Alternate Direction Implicit (ADI) finite volume method has been developed which numerically simulates the kinetics of cure, specifically the exothermic heat given out during the cure reaction of thermosetting resin.