TY - JOUR

T1 - Tailoring electrostatic surface potential and adsorption capacity of porous ceramics by silica-assisted sintering

AU - Antink, Marieke M.Hoog

AU - Beutel, Sascha

AU - Rezwan, Kurosch

AU - Maas, Michael

N1 - Funding Information: This work was supported by the German Research Foundation (DFG), Grant No. MA 4795/13-2.

PY - 2020/8

Y1 - 2020/8

N2 - In this study, we apply silica-assisted sintering to develop porous yttria stabilized zirconia (YSZ) ceramics with tailored electrostatic surface potential and adsorption capacity as a promising alternative to chemical functionalization. The porous bodies were formed by partial sintering at 1050 °C and were investigated regarding the influence of admixtures of silica particles on sintering behavior, microstructural evolution and the resulting mechanical and surface properties of the material, particularly the surface potential. With increasing silica concentration, the sintering mechanism was gradually changed from solid state to liquid phase sintering, due to the wetting of YSZ by liquid silica and a resulting inhibition of mass transport, particle growth and diffusion-induced densification. Most importantly, due to the silica layer development, the isoelectric point (IEP) of the YSZ/silica material surfaces was systematically shifted towards the IEP of silica from pH 9.4 to 1.2 resulting in a more pronounced negative surface potential at neutral pH. The relationship between surface IEP and silica concentration was mathematically described using the IEPs of the starting materials, the YSZ particle radius and the glass layer thickness. This estimation allows us to tailor the surface coverage of the YSZ matrix with silica as well as the resulting electrostatic surface potential. We further demonstrate how the applied processing route can be effectively used to develop ceramics with specified adsorption capacities for protein immobilization for use in filtration, bioprocessing or biomaterial applications.

AB - In this study, we apply silica-assisted sintering to develop porous yttria stabilized zirconia (YSZ) ceramics with tailored electrostatic surface potential and adsorption capacity as a promising alternative to chemical functionalization. The porous bodies were formed by partial sintering at 1050 °C and were investigated regarding the influence of admixtures of silica particles on sintering behavior, microstructural evolution and the resulting mechanical and surface properties of the material, particularly the surface potential. With increasing silica concentration, the sintering mechanism was gradually changed from solid state to liquid phase sintering, due to the wetting of YSZ by liquid silica and a resulting inhibition of mass transport, particle growth and diffusion-induced densification. Most importantly, due to the silica layer development, the isoelectric point (IEP) of the YSZ/silica material surfaces was systematically shifted towards the IEP of silica from pH 9.4 to 1.2 resulting in a more pronounced negative surface potential at neutral pH. The relationship between surface IEP and silica concentration was mathematically described using the IEPs of the starting materials, the YSZ particle radius and the glass layer thickness. This estimation allows us to tailor the surface coverage of the YSZ matrix with silica as well as the resulting electrostatic surface potential. We further demonstrate how the applied processing route can be effectively used to develop ceramics with specified adsorption capacities for protein immobilization for use in filtration, bioprocessing or biomaterial applications.

KW - Electrochemical characterization

KW - Liquid phase sintering

KW - Microstructure formation mechanism

KW - Structure-property relationship

KW - Yttria-stabilized zirconia polycrystal

UR - http://www.scopus.com/inward/record.url?scp=85085995108&partnerID=8YFLogxK

U2 - 10.1016/j.mtla.2020.100735

DO - 10.1016/j.mtla.2020.100735

M3 - Article

VL - 12

JO - Materialia

JF - Materialia

SN - 2589-1529

M1 - 100735

ER -