The controlled self-assembly of polymer-stabilized quantum dots (QDs) into mesoscale aqueous spherical assemblies termed quantum dot compound micelles (QDCMs) using a two-phase gas-segmented microfluidic reactor is described. Self-assembly is initiated by the fast mixing of water (approximately 1 s) with a blend solution of polystyrene-coated QDs and amphiphilic polystyrene-block-poly(acrylic acid) stabilizing chains via chaotic advection within liquid plugs moving through a sinusoidal channel. Subsequent recirculating flow within a post-formation channel subjects the dynamic QDCMs to shear-induced processing, controlled via the flow rate and channel length, before a final quench into pure water. During processing, larger QDCMs within the initial population undergo breakup into smaller particles, resulting in smaller mean particle sizes, smaller relative standard deviations, and more skewed distribution shapes, as the overall shear exposure is increased. For these cases, shear-induced size reduction is sufficient to dominate surface tension-driven growth.

The controlled self-assembly of polymer-stabilized quantum dots (QDs) into mesoscale aqueous spherical assemblies using microfluidics is described. In a flow-focusing configuration, self-assembly is initiated by the addition of water to a blended solution of polystyrene-coated QDs and amphiphilic polystyrene-block-poly(acrylic acid) stabilizing chains and terminated in a downstream quench step. The on-chip evolution of assemblies is monitored through fluorescence microscopy, and particle size distributions are determined off-chip by transmission electron microscopy. On-chip size control of the assemblies is demonstrated via both the average water concentration in the channel and the flow rate.

The controlled self-assembly of polymer-stabilized CdS quantum dot nanoparticles into quantum dot compound micelles (QDCMs) using microfluidics is demonstrated. In a flow-focusing configuration, water is introduced to a blend solution of block copolymer-stabilized quantum dots with amphiphilic block copolymer stabilizing chains. QDCM assembly via initial phase separation and subsequent agglomeration continue until a downstream quench step. Control over mean particle size and size distribution characteristics is demonstrated via both inlet concentrations and flow rate. The QDCMs assembled through this method are stable in aqueous solutions, and show internal and external structure in keeping with previous assembly methods. The on-chip evolution of QDCM formation and growth is resolved through fluorescence scattering. Particle size distributions and associated statistics are determined through off-chip analysis.