Friday, January 27, 2023 12pm to 1pm
Friday, January 27, 2023 12pm to 1pm
About this Event
29 Oxford Street, Cambridge, MA 02138
https://events.seas.harvard.edu/event/multi-scale_textured_surface_designs_with_passive_anti-frosting_capabilitiesThe need for anti-frosting surfaces is continued and ever-present. Whereas de-icing surfaces aim to reduce the adhesion of frost for easy removal, anti-frosting surfaces aim to intrinsically resist frost formation. Long-term frost resistance is incredibly valuable for regions that regularly experience freezing conditions, especially for above-ground power/telecommunications cables, aircraft airfoils, and satellite dishes, among numerous other applications.
Here, we introduce new guidelines for multi-scale surface designs that passively promote increased frost-free regions over long periods of time. By combining geometries and material properties over multiple length scales, we can effectively manipulate the diffusion flux field of incoming water vapor to create two distinct regions: (1) a small, sacrificial region with the majority of frost growth and (2) a large non-frosted region that resists frost growth over time. While millimeter-sized features alone can partially have this effect (i.e. frost-free areal portion = ~38%), it can be enhanced to a frost-free areal portion of nearly 95% by the addition of Graphene Oxide (GO) dough. Utilizing the properties of GO doughs, namely permeability and anisotropic heat transfer, in conjunction with anisotropic mass transfer on macrotexture, we can successfully control the size of the frost-free region for longer than several days, thereby mitigating frost-related material/performance degradation.