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Electrohydrodynamic Co-Jetting of Particles and Fibers

Background 

Electrohydrodynamic (EHD) co-jetting is a process developed in the Lahann lab for creating anisotropic microto nanometer-sized particles and fibers for use in the next generation of ‘smart’ devices. While standard technologies focus mainly on manipulating particle size and shape, EHD co-jetting explores the newest frontier of particle technologies by not only allowing control over particle size and shape, but also over the distribution of matter within the particles it generates. This enables desired chemical and physical properties to be compartmentalized in a single designer particle. Introducing multiple compartments with different chemical functionalities on a single particle can be employed to maximize particle function, utility, and efficacy. 
Technology 

In short, EHD co-jetting is an economical, scalable, and robust technique for producing polymeric particles or fibers with various compartments. This is achieved by pumping two polymer solutions through parallel capillaries at a laminar flow rate. Upon application of a large electric field, the fluid expelled from the capillaries gets stretched and thinned as it accelerates towards a grounded electrode. During this stretching process, the solvents readily evaporate out of the polymer solution leaving only micro-to-nanometer scale Janus particles on the grounded electrode. Due to the laminar flow rate of the solutions, three, four, or even more distinct compartments can be obtained by using the corresponding number of capillaries running in parallel. By controlling various parameters such as applied electric field, polymer concentration, flow rates, viscosity, and conductivity, a large variety of particle shapes, sizes and surface features can be achieved. At the proper polymer concentrations and viscosities, continuous jets of anisotropic polymer fibers can also be attained, opening a whole new range of potential applications for EHD co-jetting.

Advantages 

• Simple instrumentation at low cost
• Adaptable to a wide range of materials 
• Flexibility in particle shapes and morphologies 
• Controllable particle size over several orders of magnitude 
• Scalable