Pak Sang Leung

Surfactant Micelle Enhanced Ultrafiltration

A large pore size ultrafiltration membrane usually cannot be used to separate small molecules. Even some tight and low-flux reverse osmosis membranes cannot separate small molecules, eg. phenol molecules. The high phenol solubility in the membrane phase is the difficulty. If the small molecules are held by larger particles, separation can be easily done by ultrafiltration and in high flux. We are reporting the ultrafiltration of small molecules, eg. phenol, bromophenol and metallic-ion chelating agents by the addition of micelle-forming surfactants. The affinity of these small molecules to the large micelle particles contributes to a high efficiency ultrafiltration separation.

Interpolymer Complexes between Hyaluronan and Cationic Cellulose Polymers

The past decade has marked a rapidly growing interest in topical applications of both hyaluronan and cationic cellulose polymers. Because of their polyelectrolyte character and opposite charge, they can form strong interpolymer complexes with novel properties and significantly enhanced utility. This paper will describe the physiochemical properties and applications of complexes formed between hylan (a modified hyaluronan) and cationic cellulose polymers. The effect of charge density and hydrophobe content of the cellulosics on water solubility and stability of the complexes will be outlined. For stable water soluble complexes, the rheological properties of their solutions will be described, and conditions for optimizing their viscoelastic properties will be defined. The utility of the interpolymer complexes between hylan and cationic cellulosics will be demonstrated in terms of their rheological synergy and their enhanced substantivity to keratinous substrates. The latter has been determined by ESCA analysis and radiotracer studies.

Mathematical Simulation for Membrane Filtration Systems

Abstract Time variation in filtration systems variables, e.g., concentrations, volume, and permeation rate, is mathematically simulated. Rigorous mathematical solutions are illustrated for a physical model with stepwise approximation. A detailed setup for numerical calculations is given.