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Duolayers at the air/water interface: improved lifetime through ionic interactions
journal contribution
posted on 2016-01-01, 00:00 authored by Emma PrimeEmma Prime, D H Solomon, I J Dagley, G G QiaoIonic interactions to stabilize Langmuir films at the air/water interface have been used to develop improved duolayer films. Two-component mixtures of octadecanoic (stearic) acid and poly(diallyldimethylammonium chloride) (polyDADMAC) with different ratios were prepared and applied to the water surface. Surface pressure isotherm cycles demonstrated a significant improvement in film stability with the inclusion of the polymer. Viscoelastic properties were measured using canal viscometry and oscillating barriers, with both methods showing that the optimum ratio for improved properties was four octadecanoic acid molecules to one DADMAC unit (1:0.25). At this ratio it is expected multiple strong ionic interactions are formed along each polymer chain. Brewster angle microscopy showed decreased domain size with increased ratios of polyDADMAC, indicating that the polymer is interspersed across the surface. This new method to stabilize and increase the viscoelastic properties of charged monolayer films, using a premixed composition, will have application in areas such as water evaporation mitigation, optical devices, and foaming.
History
Journal
Journal of physical chemistry BVolume
120Issue
30Pagination
7401 - 7407Publisher
American Chemical SocietyLocation
Washington, D.C.Publisher DOI
ISSN
1520-6106eISSN
1520-5207Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2016, American Chemical SocietyUsage metrics
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