High aspect ratio, microstructure-covered, macroscopic surfaces

Abstract

The performance of many macroscopic structures (those whose dimensions are on the order of centimeters, meters, or even larger) can be greatly improved by covering their surfaces with microstuctures. There are several applications in which 'large,' microstructure-covered sheets are useful. For example, dissimilar sheets of material that otherwise would not bond well to one another (such as a polymer and a metal) can be more strongly bonded with microstructures extending from one of the sheets and embedded into the other sheet. Such products make valuable laminate composites. As another example, the rate of heat transfer between an object and the surrounding medium can be dramatically changed (up or down) by covering the surface of the object with high aspect ratio microstructures, without significantly changing the component's size or weight. As compared to prior thermal barrier coatings, when microstructures are thus used to cover turbine blades the turbines can operate at substantially higher temperatures (as much as 290.degree. C. higher than otherwise possible) and substantially higher pressures, while simultaneously reducing thermal stresses. Yet another application is the use of microstructures as acoustic absorbers, to reduce the amplitude of sound transmitted through a surface.