title: Effect of cosolvents on the binding interaction between poly(ethylene oxide) and sodium dodecyl sulfate.
abstract: The micellization of sodium dodecyl sulfate (SDS) in different glycol-water solvent mixtures was studied using the isothermal titration calorimetric (ITC) technique. At the same time, microcalorimetric titrations were also carried out to monitor the binding interaction of SDS and poly(ethylene oxide) (PEO) in the presence of different cosolvents. The demicellization of SDS in mixtures of water and cosolvents is different from that in water due to the reduction in solvent polarity and charge interaction of surfactants. The critical micelle concentration (cmc) first decreases with the addition of a small amount of cosolvents and then increases at higher cosolvent concentrations. The thermodynamics of surfactant micellization can be analyzed using the solubility parameters of solvent mixtures. For the binding interaction between SDS and PEO in different solvent mixtures, the dehydration process at low SDS concentrations is replaced by the chain solubilization process with decreasing solvent polarity. With further reduction in the solvent polarity, the binding interaction between SDS and PEO becomes weak and no aggregates can be formed beyond a certain glycol concentration. The binding interaction between SDS and PEO in different solvent mixtures was analyzed and ascribed to the effects of PEO solubility and hydrophobicity of SDS.
authors.affiliation: Singapore-MIT Alliance and School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Republic of Singapore.
authors.forename: Sheng
authors.initials: S
authors.lastname: Dai
authors.forename: Kam Chiu
authors.initials: KC
authors.lastname: Tam
mesh_terms: D003124:Colorimetry; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D011092:Polyethylene Glycols / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*
chemical_list: D008823:Micelles; D012997:Solvents; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols