Adsorption of lysozyme on membrane material and cleaning with non-ionic surfactant characterized through contact angle measurements

Membrane surface characterization was studied by contact angles using both a goniometer and a tensiometer. It was checked that static and dynamic advancing contact angles of ultrafiltration membranes with water were in very good agreement. For glycerol and α-bromonaphthalene, dynamic advancing contact angles were sometimes different. Protein adsorption on polyethersulfone (PES) membrane was well evidenced whatever the solvent and closely related to the drying procedure. The efficiency of a nonionic surfactant (Tween 20) to desorb lysozyme from PES was discussed according to contact angles measured in the three liquids. Dynamic advancing contact angle of water on membrane after immersion-emersion loops was decreased and afforded likely a better characterization (polar contribution) of the membrane working in filtration conditions.

Static and dynamic contact angles of water on membranes were in good agreement. For glycerol and α-bromonaphtalene, dynamic contact angles were sometimes different and did not allow concluding about the total efficiency of Tween 20 to desorb lysozyme from PES membrane. We have thus shown that dynamic contact angle measurements of membrane with water using immersion-emersion loops allow characterising the membrane properties (such as its polar component of surface free energy) in the real conditions of membrane use during filtration process.