Preparation of LB Built-up Films of Polymerizable Amphiphile with Sodium Sulfonate Group and Their Surface Properties

A new amphiphile with a sodium sulfonate group and two polymerizable alkyl chains, sodium 1,2-bis [16-(acryloyloxy)hexadeeyloxycarbonyl]ethanesulfonate (2 AC₁₆SNa), was synthesized. 2 AC₁₆SNa monolayer on the pure water surface was built-up on the polymeric substrate film (polystyrene or polyethylene) successively by applying Langmuir-Blodgett method by use of oleic acid as piston oil. The monolayer was not built-up on the polymeric substrate when the substrate moved down into the water but was built-up when it moved up from the water. From the area variation of the 2 AC₁₀SNa monolayer on the water surface during the built-up process, the film must be built-up as a Z-membrane. However, it became apparent from X-ray study that the finally obtained built-up film was Y- membrane. 2 AC₁₆SNa monomers in the built-up film were polymerized by UV-irradiation. The X-ray pattern of the polymerized 2 AC₁₆SNa built-up film was similar to that of the monomer film. This result indicates that polymerization proceeds, maintaining highly oriented bimolecular structure. When UV-irradiation was carried out in water, the surface of the polymerized built-up film was very hydrophillic. This indicates that sodium sulfonate groups are highly oriented on the built-up film surface. Blood compatibility of the polymerized built-up film was evaluated from the interaction with human blood platelets. The number of adhered and deformed platelets on the built-up film surface was less than that of the polyethylene surface which was used as a substrate, and almost comparable with that of the poly(urethane-urea) surface which shows relatively excellent blood compatibility.