This technology can fabricate highly aligned polymer films that are meters long. These films can be used in heat transfer applications such as electronic packaging and heat exchangers or can become structural components with lamination. This process is also compatible with polymer-based composites, which allows filler materials (e.g. carbon nanotubes or graphene) that can further enhance the mechanical, thermal, and electrical properties of the resulting material.
Current fabrication methods for highly aligned polymer films (HAPFs) are limited to manual, lab-scale batch processes. This process is an automated fabrication platform, the size of a printer, that can produce high crystallinity and orientation polyethylene films with draw ratios exceeding 100x.
This fabrication process consists of three steps; sol-gel extrusion, structure freezing and drying, and a mechanical drawing process. The first step involves subjecting the polymer-solvent solution to a high shear, high temperature, Couette flow extrusion into a thin film, resulting in initial disentanglement. Next, the extruded film is frozen using a liquid nitrogen cooled substrate. During this step, the solvent is removed from the polymer gel through ambient evaporation. Finally the dried film is mechanically drawn in a heated enclosure using a constant-force adaptive-thickness drawing system. The performance of this system has been confirmed by creating highly aligned polyethylene films meters long with draw ratios exceeding 100x and high crystallinity and orientation.
Allows large-scale HAPF fabrication
Compatible with polymer-based composites