Monomer Concentrations in Simple Micellar Systems from NMR Relaxation Times and C‐13 Chemical Shifts

Autor:	D. Gerrard Marangoni, Trudy A. Taylor, Maria K. Mullally, Michael D. Wilson, Michael J. Doyle
Rok vydání:	2008
Předmět:	Polymers and Plastics Thermodynamics of micellization Relaxation (NMR) Analytical chemistry Spin–lattice relaxation Micelle Surfaces Coatings and Films chemistry.chemical_compound Monomer chemistry Pulmonary surfactant Bromide Critical micelle concentration Physical and Theoretical Chemistry
Zdroj:	Journal of Dispersion Science and Technology. 29:366-374
ISSN:	1532-2351 0193-2691
DOI:	10.1080/01932690701716119
Popis:	The monomer concentrations for some simple micelle forming surfactants, octylammonium bromide (OTAB), sodium decyl sulphate, SDecS, and dodecyltrimethylammonium bromide (DTAB) were determined from the NMR‐paramagnetic relaxation enhancement experiment (the NMR‐PRE) on the H‐1 spin lattice relaxation times for the surfactant protons as a function of the surfactant concentration above and below the critical micelle concentration (cmc region). The NMR relaxation times, determined from the inversion recovery method, decrease steadily as the concentration of the surfactant is increased above the cmc value. A second, simple method is proposed whereby the p‐value of the surfactant in the micelle is determined from the two‐site model via extrapolation of the observed relaxation rate data to high concentrations. The p‐values and the calculated monomer concentrations are compared to each other and to those obtained using the mass‐action and phase separation models. In most cases, the monomer concentrations appear t...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8cb9d3f7b8d44eac7e9e651ccd545d29 https://doi.org/10.1080/01932690701716119 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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