Synthesis and polymerization of the 16-(methacryloyloxy)-hexadecanoic acidand phospholipid in monolayers

Two surface-active monomers with methacrylic group at the end of hydrophobi c tail : 16-(methacryloyloxy)hexadecanoic acid (16-MAHDA) and bis[16-(metha cryloyloxy)hexadecanoil]-phosphatidylcholine (16-MAHDPC) have been synthesi zed and investigated. The monomers form stable monolayers at the liquid/gas interfaces with liquid-expanded and liquid-condensed states at low and hig h surface pressures, respectively. These monomers have been polymerized in the monolayers by low intensity UV-irradiation (254 nm). Dependences of pol ymerization rate vs. surface pressure for both monomers have maxima (3.4.10 (-4) s(-1) for 16-MAHDA and 5.5.10(-4) s(-1) for 16-MAHDPC) at about 12 mN/ m. The higher rate of 16-MAHDPC polymerization as compared to 16-MAHDA is d ue to the two polymerizable group in the molecule of lipid as compared to t he only one in the molecule of acid. The collapse pressures increase after monomer polymerization that evidences an increase of the monolayer stabilit y in the case of polymer as compared to monomer.