Infrared and Fluorescence Spectroscopic Studies of Self-Assembled n- Alkanoic Acid Monolayers
Abstract
Infrared and fluorescence spectroscopic methods were used to study the kinetics and thermodynamics of the formation of self-assembled films of n- alkanoic acids by adsorption from solutions. The adsorption of stearic acid from hexadecane solutions onto glass and aluminum substrates was shown to lead to monolayer formation. A Langmuir-type transient adsorption model was shown to be applicable to these systems. The stationary fluorescence spectroscopy of a pyrene-labeled alkanoic acid probe was also used to determine the relative values of the kinetic constants of various fatty acids having different number of carbons in the chains. A linear increase of approximately 230 cal/mole in the negative free energy of adsorption with increasing chain length of the fatty acids was found. This attributed to the energetic contribution of the molecular organization of the aliphatic chains to the self-assembly process.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 1989
- Accession Number
- ADA208893
Entities
People
- C. W. Frank
- ShuâHsia Chen
Organizations
- Stanford University