"V-shape" molecular configuration of wax esters of jojoba oil in a Langmuir film model

MARTINI, FLORENCIA; BENJAMÍN CARUSO; MARÍA ANGÉLICA PERILLO; BENJAMÍN CARUSO; MARÍA ANGÉLICA PERILLO; PICKHOLZ, MÓNICA; PICKHOLZ, MÓNICA; MARTINI, FLORENCIA

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2018 vol. 34 p. 7887 - 7898

0743-7463

The aim of the present work was to understand the interfacial properties of Jojoba oil (JO), a complex mixture of wax esters (WEs). Previously, based on molecular area measurements, a hairpin structure was proposed as the hypothetical configuration of WEs allowing their organization as compressible monolayers at the air-water interface. In the present work we contributed with further experimental evidences by combining surface pressure (pi), surface potential (DV) and PM-IRRAS measurements of JO monolayers and molecular dynamic simulations (MD) on a modified JO model. WEs, both self-assembled in Langmuir films. Compression isotherms exhibited a pi_lift-off at 100Å2/molecule mean molecular area (A_lift-off) and a collapse point at pi_c=2.2mN/m and Ac=77Å2/molecule. The DV profile reflected two dipolar reorganizations one of them at A>A_lift-off due to the release of loosely bound water molecules and another one at Ac