The fabrication of particles with controlled anisotropy and sequence is important to their emerging applications in self-assembly, barcoding and drug delivery. Techniques such as droplet generation and continuous flow lithography have been developed to synthesize anisotropic particles. Here we present a method capable of combining both shape and material anisotropy in the same particle by microfluidic processing of solid precursors. In the process, particles of variable material and chemistry are microfluidically transported into a production zone of a microfabricated device. Anisotropic particle shape is controlled by varying the ratio of the dimension of the input particles to that of the microfluidic channel. An on-chip resistive heater is fabricated on the backside of the device in order to increase the temperature to near the glass transition temperature of the input latex particles. The particles are permanently bonded in an anisotropic configuration by this thermal fusing step. After bonding, the particle is released by reversing the flow through the production zone. The pressure-controlled synthesis can be programmed so that complex anisotropies can be obtained by the sequential actuation of metering lines that input particles of different material and chemistry. We have synthesized linear chains and triangular prisms with homogeneous (ie “A”) and heterogeneous (ie “A-B” and “A-B-A”) structure. These anisotropic particles contain specifically designed bond angles and compositions.

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