3D Printing of Polyelectrolyte Complexes: From Rheogical Optimization to Biomaterials

Polyelectrolytes have a unique property of complexation when oppositely charged paired polymers form films or coacervates. They have found applications in diverse fields, including drug delivery, wastewater treatment, and tissue engineering. With 3D printing, using polyelectrolytes presents an exciting opportunity for precisely fabricating functional materials and devices. However, the strong electrostatic interactions and the complex formation as coacervates are unstable as viscoelastic materials hinder the flow and processability of inks during the direct ink writing (DIW) process. They have been mostly demonstrated by 3D printing in support media. This talk will focus on the use of polyelectrolyte complexes (PECs) suitable for DIW, in air to form complex shapes and objects. To make PEC-based inks amenable to 3D printing in air, a wash-out deplasticizing procedure was developed. Studies on different formulations were developed that meet the printability of polyelectrolyte complexes and their rheological requirements based on the use of nanoparticles, water-soluble polymers, and ampholytes. Our investigation entailed systematically exploring solvent composition, pH conditions, and the incorporation of specific additives. Furthermore, we evaluate how these ink formulations impact the final printed structures' fidelity, mechanical properties, and complexation behavior. The findings have the potential to enlarge the way we design and manufacture PEC functional materials across diverse applications, from biomedicine to electronics by harnessing the properties of polyelectrolyte complexes