Precision Microengineering of Curved Metallic Heat Transfer Surfaces for Fouling Inhibition

Crystallization fouling, an undesirable process where scale forms on surfaces, is pervasive in nature and technology, negatively impacting the energy and water industries. Work has progressed towards realizing surfaces with intrinsic antifouling properties, however, realizing precise, defect-free topography over large areas with complex curvature remains challenging. In this work, we successfully developed a technique allowing us to impart precise surface microstructure array patterns onto metallic heat transfer surfaces with isotropic and anisotropic curvatures. The patterning on curved surfaces is realized by four steps: photoresist microstructure generation on planar substrates; structure transfer to curved metallic surfaces under heat and pressure; metal deposition by electroplating/electroless plating; photoresist removal. We conducted preliminary tests on the heat transfer performance of copper substrates with and without micropatterns in heat-exchanger-like conditions and the results show that the surface micropatterns can effectively modify the heat transfer coefficient of the metallic substrate and the structures possess good tolerance to fluidic friction. Durable curved (super)hydrophobic metallic surfaces can be realized with such stable microstructures, which are promising to mitigate fouling issues and energy loss by inhibiting the onset of nucleation and reducing the adhesion of limescale crystallites.