(177f) In-Suspension Fabrication of Multi-Material Colloidal Doublets

Studies have shown that by drastically increasing the ionic strength of a colloidal suspension, particle aggregation will occur. However, little has work has been done to control the aggregation to make useful colloidal particle aggregates. We demonstrate a simple in?suspension technique that produces designed homodoublet and heterodoublet particle aggregates of different materials and functionalizations by controlling the aggregation of the particles. The doublets are created by increasing the ionic strength of the particle solution to cause the particles to aggregate together. The reaction is then quenched by quickly decreasing the ionic strength before larger particle aggregates have the chance to form. These doublets can be permanently stuck together through a pressurized high temperature in-solution fusing or chemical fusion. The effectiveness of the fusing process is demonstrated by the stability of the doublets during intense sonication and agitation, while without the fusion step the doublets break apart. This doublet formation technique is advantageous because it is a simple?to?perform, quick, and repeatable process for creating controlled non-spherical colloidal particle doublets. Results are presented for the fabrication of polystyrene latex homodoublet and heterodoublet fused aggregates of various functionalizations. In addition, results are shown for the application of the salting out?quenching?fusing technique to colloids of different materials with varying glass transition temperatures. The effect of the fusing process on the surface charge of the formed polystyrene latex doublets is discussed.