Critical Aggregation Behavior of SDSPEI Mixtures in Bulk Solution and in Multilayer Films
Date of Award
2005
Document Type
Thesis
Degree Name
Bachelors
Department
Natural Sciences
First Advisor
Johal, Malkait
Keywords
Critical Aggression, Self-Assembly, Polymer-Surfacant, PEI SDS PAZO Multilayer
Area of Concentration
Natural Sciences
Abstract
This work explores the critical aggregation interactions between a polyelectrolyte and an oppositely-charged surfactant. Mixed solutions were prepared from the anionic surfactant SDS (sodium dodecyl sulfate) ranging in concentration from 0 to 1 mM and were diluted in 1 mM PEl (poly (ethylenimin)). A break point in the curve of surface tension plotted as a function of SDS concentration revealed a critical aggregation concentration (CAC) around 0.01 mM SDS. (PEI/SDS/PAZO)n (n = 1 to 10) trilayers were electrostatically adsorbed from solutions containing fixed 1 mM amounts of PEl and PAZO (poly{I-4[4-(3-carboxy-4-hydroxyphenylazo )benzenesulfonamido]-1,2-ethanediyl sodium salt}). The SDS solution concentration was varied among films from 0 to 0.1 mM. After each P AZO deposition step, trilayer thicknesses and absorbances were found to increase with decreasing SDS concentration except in the case for 0.1 mM SDS, yielding trilayers having the highest thicknesses and second-highest absorbances. Film growth at post-CAC concentrations is attributed to hydrophobic interactions between SDS and PAZO layers. PEI/SDS bilayers were similarly assembled from fixed amounts of 1 mM solutions. The films showed little growth until the 9th bilayer, which was attributed to hydrophobic as well as electrostatic interactions between SDS alkyl chains and PEl. This finding supports evidence for hydrophobic binding between SDS and PAZO layers in multilayered assemblies. This work provides fundamental understanding of the critical aggregation interactions occurring in multilayer films assembled from polyelectrolytes and surfactants.
Recommended Citation
Hicks, Raea, "Critical Aggregation Behavior of SDSPEI Mixtures in Bulk Solution and in Multilayer Films" (2005). Theses & ETDs. 3531.
https://digitalcommons.ncf.edu/theses_etds/3531
Rights
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.