Clustering Colloids with Polymer Bridges

Colloidal model systems are typically highly uniform, yet structurally simple. One design principle inspired from organic chemistry is to take rudimentary atomic building blocks and combine them into more complex and functional molecules. An analogous colloidal reaction is the heteroaggregation of core and shell particles into clusters that have new shapes, which can foster assembly in a directional fashion. Some colloidal pairings are naturally complementary, such as oppositely charged particles, but it is difficult to combine distinct like-charged suspensions in a similar manner. Highly tailored surface chemistry can bind particles together, however, severely impact throughput along the way. Here, a general approach to heteroaggregation is described where particles are speciated as either polymer-coated or bare and made to bind specifically to their counterpart through polymer bridging. Flexibly selecting from a variety of materials for the cores and shells creates a veritable zoo of different cluster products with large-scale production potential. Harnessing this colloidal bond has led to advancements in particle shape, surface pattern, and regioselective binding, which are all necessary control parameters for furthering our capabilities in synthetic self-assembling systems.