Figure 2: Peel test measurements for Au on Al.

(a) Schematic of 90° peel test applied to a layer of Au on top of a uniform layer of ODPA-coated Al. (b) Photograph showing the tape after peeling, with removed Au visible on the tape. (c) Peel curves for a layer of Au on top of a uniform layer of Al, with and without an intervening ODPA layer. Without ODPA, the applied force peaks at a high value of ~\n1.6 N, before decreasing to a lower steady state value of ~\n1.4 N. With ODPA, the applied force peaks at a much lower value of~\n0.2 N before falling to a steady state value of~\n0.16 N. (d) Schematic of 90° peel test as applied to a uniform layer of Au deposited on a line array of ODPA-coated Al with spacings, widths and lengths of 4, 1.2 and 20 mm, respectively. (e) Photograph showing the tape after peeling, with removed gold visible on the tape. (f) Peel curves for Au films on top of ODPA-coated Al line arrays, using insulation tape or solution-coated glue as the adhesive layer. In the case of the tape, a linear increase in the peeling force from ~\n0.16 N to ~\n1 N is observed as the peel edge passes across the (Al-free) regions between lines. This is followed by a rapid decrease to ~\n0.16 N as the peel edge passes onto the ODPA-coated Al, and the tension drops due to the weakened adhesion. In the case of the glue, a similar peeling force of ~\n0.16 N is measured when the peel edge is above the Al lines but the behaviour in-between lines is different, with the peeling force stabilizing rapidly to ~\n0.35 N. Inset is a photograph of the final patterned structure. See Supplementary Note 1 for a discussion of all four peeling curves.