Electrothermal patches and Nanohole calculations

For the work Nanoscale Horizons (2019) I did numerical calculations of the joule heating of a nanostructured gold film carrying an electrical current. The nanostructured films were obtained from the deposition of gold on self ordered polystyrene micro/nano-spheres layer, resulting in thin gold film with a nearly-periodic array of holes. The calculations follow 3 stages.

• Calculating joule heating of a periodic film with holes, to obtain effective electrical and thermal conductivities.
• With effective conductivities, perform 3D calculation, considering the gold film as a 2D surface satisfying the Laplace equation.
• Obtain analytical steady state temperatures. 

Calculations were performed with the FEM software COMSOL. Surprisingly, a simple analytical model is very precise in fitting the Temperature-Voltage or Temperature-current at equilibrium, and allows the easy derivation of the heat transfer parameter.
It was fun also removing kapton from a kapton/copper laminate by laser ablation. The process leaves a dark oxide  on the copper layer that can be easily removed with a warm acetic acid solution in ultrasonic bath.