Fig. 7
From: Substrate geometry modulates self-assembly and collection of plasma polymerized nanoparticles
Schematic comparing nanoparticle aggregation on wells of different aspect ratios. a In 6- and 12-well plates, dsheath << rwell (dsheath is the length of the plasma sheath and rwell is the well radius) and the plasma expands through most of the well. The particles (with radius rp) continue to grow and build-up charge inside the wells and interparticle electrostatic repulsion prevents aggregation. b Plasma expansion inside wells of 24- and 48-well plates is insufficient and “electrostatic lensing effect” concentrates particles around the well central axis. Radical sticking overcomes Coulomb repulsion downstream the plasma sheath in the well triggering nanoparticle aggregation. c “Electrostatic lensing effect” is mitigated in 96-well plates since dsheath ≈ rwell. The aggregation probability between nanoparticles is reduced due a reduced particle density inside the wells. Scale bars are 5 µm
