Figure 1
Preparation of High-Density Lattices of Micrometric Suspended F8BT Membranes by Capillarity-Driven Solvent Evaporation. (a,b,f,g) Bright-field (a) and fluorescence (b,f,g) optical images showing a top-view of suspended F8BT membrane lattices prepared drop-casting 10 μL of 1 wt% polymer solution onto silicon microstructured templates featuring 2D arrays of open-ended micropipes with pitch of 8 (f), 4 (a,b), and 3 μm (g), with insets highlighting a 10 × 10 μm2 area. (c,d) SEM micrographs showing a bird’s-eye view (c) of the membrane lattice reported in (a,b), with inset highlighting a single suspended membrane at higher magnification, and a cross-section view (d) obtained by FIB milling process along the red dashed line in (c). (e) Sketch showing the phases of membrane formation: (e-1) polymer filled open-ended micropipes resulting from capillarity-driven flow developing along the pipes, from inlet (top) to outlet (bottom), after drop-casting deposition, (e-2) formation of a continuous polymer layer covering the silicon microstructure upon solvent evaporation from the solution on top of the microstructure, (e-3) flow menisci moving backward upon solvent evaporation from the solution within the pipes, (e-4) suspended polymer membrane formation at the inlet of open-ended pipes after full solvent evaporation. (h) Fluorescence optical image showing typical μQRs of suspended F8BT membranes obtained drop-casting 5 μL of 1 wt% polymer solution, and inset reporting a zoom on a single μQR.
