(672f) Continuous 3D Chaotic Printing: Using the Chaotic Flow Induced By a Kenics Mixer to Continuously Fabricate Complex Micro- and/or Nanostructure at High Resolution

3D printing has become a powerful tool in a wide spectrum of applications from mechanical design to biomedicine. However, the 3D printing of complex structure at high resolution and speed continues to be a challenge. To date, the robust fabrication of reproducible micro- and nanostructures in a multi-material construct through a single nozzle printer head remains to be demonstrated. Here, we use chaotic flows generated by a printing head that contains an on-line Kenics mixer with multiple mixing elements (or sections) as a strategy for continuous 3D-printing of multi-material lamellar structures with different degrees of surface area and full spatial control of the internal microstructure.

We demonstrated the use of this new printing platform by coextruding two inks consisting of a suspension of fluorescent particles (i.e., microparticles, nanoparticles, or cells) in an aqueous solution of sodium alginate through a tube containing a Kenics mixer. The outlet was submerged in an aqueous calcium chloride solution to crosslink the emerging alginate fibers, which contained a well-defined lamellar microstructure. In addition, we conducted full 3D simulations of the printing process by solving the Navier-Stoke equations of fluid motion using computational fluid dynamic (CFD) techniques. Comparison of the experimental and computational results revealed that the output of the chaotic printing process is predictable and amenable of mathematical modelling.

Continuous chaotic printing using 2 to 6 Kenics elements enables the fabrication of predictable structure in polymer constructs, reaching resolutions that range from 500µm to 31µm of striation thickness and that are conceptually capable of reaching the nanoscale by using 10 Kenics elements. This technique is fundamentally solid; it relies on the use of laminar chaotic flows to develop structure at an exponential rate in a deterministic manner. Due to the simplicity and high resolution that offers, chaotic printing could enable novel biomedical and electronic applications including the fabrication of tissue-like structures and supercatalytic materials.