Fig. 2: Polycondensation mechanism and structure of RF-acid resins.

a Polycondensation mechanism; b bridging structure; and c π-conjugated and π-stacked D–A architecture. In b, the green dots denote the sites not substituted by linkers. The structure contains 126 carbons (6 × 16 aromatics + 30 linkers), and the linker/aromatic ring ratio (= 30/16) is 1.88.