title: Kinetics and mechanisms of monolayer interactions IV: Surface activity of alkanols and energies of their interaction with dipalmitoyllecithin and dipalmitoylphosphatidylethanolamine.
abstract: The free energies of adsorption of the C1 to C14 alkanols at the air--water interface, estimated from plots of the surface pressure (pi less than or equal to 5 dynes/cm) against the bulk concentration, were a linear function of the chain length for 1-alkanols. From C3 to C8, the 2- and 3-isomers showed lower values than the 1-isomers. The energies of interaction of the C1 to C14 alkanols with dipalmitoylphosphatidylethanolamine and dipalmitoyllecithin monolayers, previously spread at the air-water interface, were estimated from the increase of the surface pressure with increasing concentrations of the injected alkanol. The energies of interaction of the C1 to C5 1-alkanols were linear functions of the chain length. The energy of interaction per methylene group of the alkyl chain suggests that the phospholipid monolayers behaved as ultrathin "oil" phases. The 2- and 3-isomers presented marked departures from linearity. The literature data for reflection coefficients in biomembranes and for partition coefficients between olive oil and water, red cell membranes and water, and phospholipid liposomes and water for the C1 to C5 alkanols show similar linearities with the chain length for the 1-isomers and comparable departures for the 2- and 3-isomers.
mesh_terms: D000327:Adsorption; D000438:Alcohols / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D008567:Membranes, Artificial; D010539:Permeability; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012996:Solutions; D013329:Structure-Activity Relationship; D013500:Surface Tension; D013816:Thermodynamics
chemical_list: D000438:Alcohols; D008567:Membranes, Artificial; D010714:Phosphatidylethanolamines; D011663:Pulmonary Surfactants; D012996:Solutions