Chika Matsunaga

Surface Modification of Complex Oxide Powder with Polyelectrolyte Layers Improving EPD Characteristics

The surface modification of Gd doped ceria (GDC) and Sr-and Mg-codoped lanthanum gallate (LSGM) powders with cationic and anionic polyelectrolytes, Poly (diallyldimethylammonium chloride) (PDDA) and poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), respevtively, was performed by the Layer by Layer (LbL) adsorption method to improve the surface-charging uniformity. The tri-layer of GDC/LSGM/GDC was deposited on a polypyrrole coated porous NiO-YSZ substrate by sequential EPD using the ethanol-based suspensions of the surface-modified powders. The topcoating of hydroxyl-propyl cellulose (HPC) on the deposited layers was conducted to control the drying rate with suppressing the cracking and peeling-off of the deposits. The advantage of the use of those polymers for the EPD process including the drying technique was demonstrated.

Fabrication of c-Axis-Oriented Zeolite L Seed Layer on Porous Zirconia Substrate by Electrophoretic Deposition in Strong Magnetic Field

Orientation technique based on the magneto-scientific crystal alignment phenomenon combined with electrophoretic deposition (EPD) technique was applied for the seeding process of zeolite L particles. Well-dispersed, ethanol-based zeolite L suspension was prepared and then consolidated on porous zirconia substrates by EPD. Conducting polypyrrole film synthesized on the zirconia substrate was used as an anodic substrate for the EPD process. The EPD was performed in a superconducting magnet with applying 12 T strong magnetic field to the suspension. The degree of orientation was characterized by XRD and compared with that of the zeolite L layer prepared by slip casting in a 12 T strong magnetic field using the same suspension.