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Biogenic amine – surfactant interactions at the air-water interface
J Penfold1, R K Thomas2, P X Li3
1ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK; Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, UK.
Journal of Colloid and Interface Science
|December 10, 2014
Summary
Polyamines and anionic surfactants form complex surface structures at the air-water interface. Changing polyamine structure and pH influences adsorption, with higher molecular weight polyamines forming ordered multilayers at lower pH.
Area of Science:
- Surface Chemistry
- Colloid Science
- Biophysical Chemistry
Background:
- Polyamines interact strongly with anionic surfactants.
- This interaction leads to adsorption at the air-water interface and can form layered structures.
- Surface structure transitions depend on pH, polyamine structure, and molecular weight.
Purpose of the Study:
- Investigate how polyamine molecular weight and structure affect adsorption of sodium dodecyl sulphate at the air-water interface.
- Examine the impact of amine group number and spacing on surface adsorption.
- Compare biogenic amines with synthetic polyamines.
Main Methods:
- Neutron reflectivity
- Surface tension measurements
Main Results:
- Ordered multilayer structures observed at pH 3-7 for higher molecular weight polyamines (spermidine, spermine).
- Monolayer adsorption with enhanced surfactant adsorption observed for putrescine (all pH) and spermidine/spermine (high pH).
- Optimal spacing between amine groups is crucial for ordered surface multilayer formation.
Conclusions:
- Polyamine structure, molecular weight, and pH are critical factors controlling adsorption at the air-water interface.
- Biogenic amines like spermidine and spermine can form complex multilayer structures under specific conditions.
- Amine group spacing significantly influences the formation of ordered surface structures, suggesting tailored polyamine design for interfacial applications.
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