PT  - JOURNAL ARTICLE
AU  - Wolf Wrasidlo
AU  - KAROL J. MYSELS
TI  - The Structure and Some Properties of Graded Highly Asymmetrical Porous Membranes
DP  - 1984 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 24--31
VI  - 38
IP  - 1
4099  - http://journal.pda.org/content/38/1/24.short
4100  - http://journal.pda.org/content/38/1/24.full
SO  - PDA J Pharm Sci Technol1984 Jan 01; 38
AB  - Some properties of a new type of membrane, a graded highly asymmetrical skinned micropo-rous membrane, are discribed and some of their rationale reviewed. The asymmetry of the new membranes as measured by the ratio of pore sizes of its two sides exceeds 100 and the pore size increases approximately exponentially across their thickness. This explains their relatively high water permeability and low surface area as well as high dirt-holding capacity. As a result, their retention is primarily mechanical-true sieving and, therefore, relatively independent of the surface properties of the particles to be retained, the nature of the carrier liquid and the rate of filtration. An unexpected and unique property due to the smoothness of the skin of these membranes is that their skin-to-skin contact is so intimate that the bubble point of a skin-to-skin sandwich is markedly higher than that of the individual components.