Patchy particles are decorated with discrete domains that have different characteristics than the rest of the surface. Fabrication strategies involving post-modification of specific surface domains generally offer better control over patch size and position.
In this study, researchers from the University of Bordeaux present a multistep approach based on electrodeposited metal layers as temporary masks. First, a close-packed monolayer of 2 μm aminated silica beads was transferred onto a gold-plated conductive substrate using the Langmuir-Blodgett technique. SEM confirms the silica particles are closely packed in a compact hexagonal lattice.
This particle array was then used as template for nickel electrodeposition. Subsequent electrodeposition of gold and nickel produced silica particles embedded in a nickel-gold-nickel stack. Layer thicknesses were 463±50 nm, 388±45 nm, and 1020±65 nm respectively.
The unmasked surface area was functionalized with azido groups. After chemical etching of nickel layers and spin-coating PMMA/PDMS, the sample was turned over to functionalize the aminated surface with FITC. The PMMA layer was dissolved, and the azidated surface was functionalized with Cyanine3 via click chemistry. Finally, the two-patch particles were isolated by dissolving the gold layer.
Confocal fluorescence microscopy confirmed two differentiated patches: one exhibiting fluorescence linked to FITC, the other to Cyanine3. By varying electrodeposition times, patch size was tunable—thicknesses of 775±60 nm, 405±40 nm, and 260±40 nm produced larger fluorescent patches as expected.
This work provides an exciting example of a strategy for producing patchy particles with two different functionalities..
DOI
10.1007/s11705-026-2631-0