title: Thermal behavior of 1,2-dipalmitoyl-sn-3-phosphoglycerocholine bi- and multi-layers, deposited with physical vapor deposition under ellipsometric growth control.
abstract: 1,2-dipalmitoyl-sn-3-phosphoglycerocholine membranes were deposited onto a silicon substrate (Si/SiO(2)) using physical vapor deposition with in situ ellipsometric thickness control. Along several heating cycles it was possible to identify well-defined boundaries for gel, ripple, liquid crystalline, and fluid-disordered phases. Particularly, the second order transition between gel and ripple phase was clearly identified in the range of ~28-34 °C using Raman spectroscopy. Atomic force microscopy and imaging ellipsometry (IE) were used to observe and characterize the ripple phase undulations of period λ = 20.8 nm and average height h = 19.95 nm along the temperature interval of ~34 to 40 °C. Clusters/agglomerations heights of more than twice the membrane thickness were observed with IE, induced by heating cycles.
authors.affiliation: Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860-Santiago, 7820436 Chile. cgonzalen@puc.cl
authors.forename: Carmen
authors.initials: C
authors.lastname: González H
authors.forename: Ulrich G
authors.initials: UG
authors.lastname: Volkmann
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Retamal
authors.forename: Marcelo
authors.initials: M
authors.lastname: Cisternas
authors.forename: Mauricio A
authors.initials: MA
authors.lastname: Sarabia
authors.forename: Karina A
authors.initials: KA
authors.lastname: López
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D002021:Buffers; D008051:Lipid Bilayers / Q000737:chemistry*; D013696:Temperature; D014835:Volatilization
chemical_list: D002021:Buffers; D008051:Lipid Bilayers; D015060:1,2-Dipalmitoylphosphatidylcholine