MONOLAYER PROPERTIES OF AN AMINE-BASED DIACETYLENE

An amine-containing diacetylenic amphiphile was prepared from pentacos a-10,12-diynoic acid. Its monolayer properties as a floating Langmuir film were investigated. As a classic long chain amphiphile, condensed monolayers of pentacosa-10,12-diynylamine exhibited high collapse pres sures and a solid-like character stable against compressive creep. A l imiting molecular area of 23 Angstrom A(2)/molecule was found, consist ent with other single chain diacetylenic amphiphiles. Isothermal compr ession studies showed a distinct transition in monolayer organization from a disordered to an ordered or solid film below a molecular area o f 25 Angstrom A(2)/molecule. The nature of the film behavior at molecu lar areas greater than the transition to the solid could be manipulate d by adjusting the subphase pH and/or the dissolved anion.