FIGS. 3A-3G show an example flexible electrical device 300 of the disclosure at intermediate stages of an example manufacturing process of the disclosure with double softening polymer layer-containing embodiments.

FIG. 3A shows the device 300 after forming a softening polymer layer 105 with a thin film electrode trace 140 thereon. As further illustrated, some embodiments of the device 300 can optionally further include a thin film electrode interaction pad 260 on the electrode trace 140.

The softening polymer layer 105, electrode trace 140 and the optional electrode interaction pad 260 can be composed of any of the materials, have any of the thicknesses, and, be formed by any of the processes, as disclosed elsewhere herein in the context of FIGS. 1A-1E and FIGS. 2A-2J and 2L-2M.

FIG. 3B shows the device 300 during an optional reactive ion etch surface treatment of an exposed surface 305 of the softening polymer layer 105 to form a treated softening polymer layer surface 310. We discovered that for some embodiments, a subsequently formed cover layer composed of the second softening polymer may not adhere as well to the softening polymer layer 105 as desired, and consequently, the layer may be prone to delamination. In some embodiments, the formation of a treated softening polymer layer surface 310 facilitates adhesion of second softening polymer cover layer to the softening polymer layer 105.