Figure 5: Sequence selective logic gates.

(a) Schematic of a double-layer protected PCDA-derived PDA film for a sequence-specific colorimetric sensor. (b) Photographs of the sensor films after exposure to IPA and toluene in different order. (c) A solvatochromic keypad lock logic circuit. (d) Film thickness as a function of distance before (black) and after protection with PMMA (blue) and PVP (green). The red line is obtained after exposure of the sensor film to IPA.