Wetting properties of phospholipid-polypeptide monolayers deposited onto polyethylene terephthalate.

The paper presents changes in wettability of the unmodified and modified polyethylene terephthalate (PET) surfaces. A low temperature air plasma was used to activate the polymer surface and to change its hydrophilic-hydrophobic properties. Then, using the Langmuir-Blodgett technique, the Langmuir monolayers of l,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cyclosporine A (CsA) with different molar fractions, i.e. χ=0.25, 0.50, 0.75, were deposited onto the activated PET surface. Besides, a series of DPPC and CsA monolayers was also transferred onto the chitosan layer, previously produced on the plasma treated PET by the dip- coating method. The wetting properties of such modified PET surfaces were then investigated by the contact angle measurements using three test liquids with well-known surface tension components. The obtained results show that wettability depends on the composition of the deposited DPPC/CsA layer with or without chitosan. Presence of chitosan makes the DPPC/CsA film surface more polar due to specific organization of molecules that expose their polar heads outside. [ABSTRACT FROM AUTHOR]