ISOTHERM AND X-RAY MEASUREMENTS OF A LANGMUIR MONOLAYER OF A NON-POLAR HYDROCARBON CHAIN MOLECULE

Mengyang Li, MICHAEL D. C. SMITH, GERREN D. SIMMS

Abstract


Traditionally Langmuir monolayers and lipids bilayers (including cell membranes) on water interfaces are made of amphiphilic molecules with both polar hydrophilic and non-polar hydrophobic parts.  It has been discovered that non-polar hydrocarbon chain molecules without the polar hydrophilic part, can also form Langmuir monolayers on water when the chain molecule has more than 30 carbon atoms.  Here we report the surface pressure vs. area isotherm measurements of a H(CH2)36H film on water, which show the film’s maximum compression modulus (greatest resistance to lateral compression) at about 19 Å2/molecule, independent of the compression speed, like the Langmuir monolayers of long chain saturated fatty acids do.  The cross-section area of the hydrocarbon chain is about 19 Å2.  Our measurements confirm the formation of a Langmuir monolayer by H(CH2)36H, a non-polar hydrocarbon chain molecule.  X-ray measurements reveal structural information of the monolayer. 


Full Text:

PDF


Copyright (c) 2017 Proceedings of the West Virginia Academy of Science

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.