Fig. 3: Assembly optimization using various solvent systems.
From: Optofluidic three-dimensional microfabrication and nanofabrication
a, Schematic illustration showing the clustering behaviours of colloidal particles in solutions with different particle–solvent affinities. b, Cluster area of SiO2 particles over time in different solvents. Data points are extracted from Supplementary Video 16 at 10-s intervals. c, Cluster area of SiO2 particles in various solvents after 60 s of laser heating at a power of 50 mW and a scan speed of 500 μm s−1. Insets are optical images of SiO2 clusters in oleic acid and silicone oil. d, Schematic illustration depicting the effect of surfactant on colloidal particle assembly in the aqueous solutions. The addition of surfactant reduces the surface tension gradient, attenuating the bubble growth and weakening Marangoni flow, thereby facilitating the particle clustering. e, Cluster area of SiO2 particles (purple spheres) and flow speed (black diamonds) in aqueous solutions with different concentrations of CTAB. Insets are optical images of SiO2 clusters in pure water and 1 mM CTAB solution. f, Cluster area of SiO2 particles in solutions containing different surfactants (1 wt% PF108, 1 wt% PEG and 8 mM SDS). Insets are optical images of SiO2 clusters in solutions of 1 wt% PF108 and 8 mM SDS. The laser power and scan speed for e and f are both 50 mW and 5 μm s−1, respectively, with a duration of 10 s. Data points are shown as mean ± s.d. with at least three independent samples/measurements (n ≥ 3). Scale bars, 30 μm (c,e,f).
