| Influence of SiO2 Content on Wet-foam Stability for Creation of Porous Ceramics |
| Subhasree Bhaskar, Jung Gyu Park, Gae Hyung Cho, Dong Nam Seo, Ik Jin Kim |
| Institute of Processing and Application of Inorganic Materials, (PAIM), Department of Advanced Material Science and Engineering, Hanseo University |
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| ABSTRACT |
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The thermodynamic instability of bubbles in wet-foam colloidal suspension is due to the substantial area of their gas/liquid interface. Several physical processes lead to gas diffusion from smaller to larger bubbles, resulting in a coarsening and Ostwald ripening of wet foam. This includes a narrowing of the bubble size distribution. The distribution and microstructure of porous ceramics, the adsorption free energy and Laplace pressure of $Al_2O_3$ particle-stabilized colloidal suspension, and $SiO_2$ content were investigated for tailoring the bubble size. Wet-foam stability of more than 80% is related to the degree of hydrophobicity with contact angles of $62-70^{circ}$ achieved from the surfactant. The contact angle replaces part of the highly energetic interface and lowers the free energy of the system. This leads to an apparent increase in the surface tension (26-33 mN/m) of the colloidal suspension. |
| Key words:
Suspension stability, Wet foam stability, Adsorption free energy, Laplace pressure, Porous-ceramics |
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