2026 Volume 69 Pages 14-21
Background and Aims: Slurries in which fine particles are highly dispersed in liquid media are utilized in a wide range of material processing, including those in the fields of energy, environment, catalysis, and pharmaceuticals. Controlling the dispersion state and assembly structure of fine particles is key to improving the handleability of slurries and the performance of the final products. Herein, we review some examples of applying a partial complex of polyethyleneimine (PEI) and fatty acids as functional polymer dispersants to control particle dispersion and assembling behaviors in liquid media. Further, focusing on ceramic processing, we demonstrate that the particle dispersion/assembling control by functional polymer dispersants can be implemented in material microstructure control and three-dimensional structuring.
Methods and Results: A complex of PEI and fatty acids was simply prepared by mixing PEI and fatty acids in nonaqueous solvents. The designed PEI based complex was found to adsorb on various series of particles which enabled to improve the dispersion stability of multi-component slurries. In addition, particle assembling control was achieved through a strategic mixing sequence of the slurries containing PEI based complex. By utilizing this particle assembling technique, the microstructure control of ceramic green bodies comprised of Si and sintering aids, which were designed for post-reaction sintering process of Si3N4 ceramics, was successfully achieved to improve material properties. Further, interparticle photo-cross-linkable slurries can be designed by the leverage of free amine groups in PEI based complex fixed on particles as cross-linking reaction sites. The designed photocurable suspension played an important role in achieving rapid 3D structuring of densified and porous ceramic components.
Conclusions (Outlooks): Partial complex of PEI and fatty acids was designed as polymer dispersants possessing multifunctional properties enabling particle dispersion control, particle assembling, and provision of stimuli-responsive reaction sites. The designed functional polymer dispersant played an important role in microstructure control and 3D structuring of ceramic components. We believe that the present technology is expected to make a significant contribution to the continued evolution of powder-based processes in materials development.
https://ror.org/03zyp6p76 