Stability of FDTS monolayer coating on aluminum injection molding tools

The injection molding industry often employs prototype molds
and mold inserts from melt spun (rapid solidification processing
[1,2]) aluminum, especially for applications in optics [3,4], photonics
[5] and microfludics. Prototypes are also used for verification
of mold filling. The use of aluminum tools has reduced lead time
(days instead of weeks) and manufacturing cost (30% of conventional
mold). Moreover, for aluminum, a surface roughness (RMS)
below 5 nm can be obtained with diamond machining [3,4,6]. Conventional
mold coatings add cost and complexity, and coatings with
thicknesses of a few microns can obliterate small features. The
nanoimprint lithography community extensively uses functional
monolayer coatings on silicon/SiO2 lithographic stamps [7–11].
This treatment dramatically reduces stiction, and improves yield
and quality of replicated nanostructures. Here we report on a fluorinated
trichloro-silane based coating deposited on aluminum or
its alloys by molecular vapor deposition. We have tested the stability
of this coating in challenging conditions of injection molding, an
environment with high shear stress from the molten polymer, pressures
up to 200 MPa, temperatures up to 250 ◦C, and rapid thermal
cycling.