Mixed monolayers of phosphatidylethanolamine and (laurylamido)-N,N'-dimethylpropylamine oxide at the air/water interface. Lateral proton conduction along a mixed structure of conducting and nonconducting entities

Abstract

A localized lateral proton pathway is present along the phospholipid polar heads and bound water molecules when the lipids are spread in monolayers at the air/water interface. Mixed films of (laurylamino)-N-N'-dimethylpropylamine oxide (LAPOA) and phosphatidylethanolamine (PE) are studied by surface pressure and fluorescene measurements. The polar head of this amphiphilic detergent shows no global electric charge but a N + ←O - dipole. The localization of this detergent at the air/water interface changes when the mixed monolayer is compressed