Structural conformation of lipids at the oil-water interface

TY - JOUR

T1 - Structural conformation of lipids at the oil-water interface

AU - Campana, Mario

AU - Webster, John R. P.

AU - Lawrence, M. Jayne

AU - Zarbakhsh, Ali

PY - 2012/9/14

Y1 - 2012/9/14

N2 - A neutron reflectivity study of the phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine at the hexadecane-water interface is reported as a function of spread amount. Two isotopic contrasts have been used to determine the structure of the phospholipid molecule in the buried interfacial region. The results indicate a roughened or diffuse monolayer at low spread amounts of phospholipid at the oil-water interface. An increase in the spread amount of phospholipid results in combination of a monolayer plus micelle-like aggregates formation at the interface. There is a transition from a monolayer to a more complex monolayer and micelle-like aggregates conformation as the amount of spread phospholipid increases. The total layer thickness for these fits is about 70 angstrom, which is much larger than a fully extended DSPC molecule (similar to 30 angstrom). This is indicative of rough molecular packing at the oil-water interface. This roughened or diffuse interface is suggested to be because of the solvation effect of the hydrocarbon tails and the resultant hydrophobic interactions. In addition, a minor contribution may originate from the accommodation of the charges in the head groups.

AB - A neutron reflectivity study of the phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine at the hexadecane-water interface is reported as a function of spread amount. Two isotopic contrasts have been used to determine the structure of the phospholipid molecule in the buried interfacial region. The results indicate a roughened or diffuse monolayer at low spread amounts of phospholipid at the oil-water interface. An increase in the spread amount of phospholipid results in combination of a monolayer plus micelle-like aggregates formation at the interface. There is a transition from a monolayer to a more complex monolayer and micelle-like aggregates conformation as the amount of spread phospholipid increases. The total layer thickness for these fits is about 70 angstrom, which is much larger than a fully extended DSPC molecule (similar to 30 angstrom). This is indicative of rough molecular packing at the oil-water interface. This roughened or diffuse interface is suggested to be because of the solvation effect of the hydrocarbon tails and the resultant hydrophobic interactions. In addition, a minor contribution may originate from the accommodation of the charges in the head groups.

U2 - 10.1039/c2sm26028j

DO - 10.1039/c2sm26028j

M3 - Article

SN - 1744-683X

VL - 8

SP - 8904

EP - 8910

JO - Soft Matter

JF - Soft Matter

IS - 34

ER -