Self-association of potassium nonanoate molecules in aqueous aerosil dispersions:13C NMR data

Результат исследований: Научные публикации в периодических изданияхстатья

1 цитирование (Scopus)

Выдержка

The association of potassium nonanoate molecules in aqueous Aerosil dispersions at high and low surface charges of its particles are studied by the 13C NMR technique at frequencies of 75 and 125 MHz with the rotation of a sample at a magic angle. It is shown that, using the chemical shifts and spin-lattice relaxation times of 13C nuclei of single segments of the hydrophobic chain of a surfactant molecule, one can determine whether the segments are located in the adsorption layer on a solid surface or in the associates formed in the bulk solution. The values of the chemical shift and spin-lattice relaxation time depend, above all, on the value of the surface charge. The NMR parameters of two carbon atoms in the hydrophobic chain nearest to the polar group of the surfactant molecule appeared to be the most sensitive to the value of the adsorbent surface charge. It is discovered that, upon adsorption of potassium nonanoate from solutions with concentrations of 1.5-3 wt % and pH 6, the surfactant molecules are located in the adsorption layer parallel to the surface. At a higher surface charge, adsorption in the same concentration range occurs mainly on the hydroxyl groups; in this case, adsorbed molecules are arranged mostly along the normal to the surface. At surfactant concentrations much higher than the CMC (10-20%), the values of the chemical shift and relaxation time become closer to those measured in surfactant solutions in the absence of Aerosil.

Язык оригиналаанглийский
Страницы (с-по)567-574
Число страниц8
ЖурналColloid Journal
Том66
Номер выпуска5
DOI
СостояниеОпубликовано - 1 сен 2004

Отпечаток

Dispersions
Surface-Active Agents
Silicon Dioxide
Potassium
potassium
Surface charge
Surface active agents
Nuclear magnetic resonance
Chemical shift
surfactants
nuclear magnetic resonance
Molecules
Relaxation time
Adsorption
Spin-lattice relaxation
chemical equilibrium
molecules
adsorption
relaxation time
Chemical relaxation

Предметные области Scopus

  • Поверхности и интерфейсы
  • Физическая и теоретическая химия
  • Коллоидная химия и химия поверхности

Цитировать

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abstract = "The association of potassium nonanoate molecules in aqueous Aerosil dispersions at high and low surface charges of its particles are studied by the 13C NMR technique at frequencies of 75 and 125 MHz with the rotation of a sample at a magic angle. It is shown that, using the chemical shifts and spin-lattice relaxation times of 13C nuclei of single segments of the hydrophobic chain of a surfactant molecule, one can determine whether the segments are located in the adsorption layer on a solid surface or in the associates formed in the bulk solution. The values of the chemical shift and spin-lattice relaxation time depend, above all, on the value of the surface charge. The NMR parameters of two carbon atoms in the hydrophobic chain nearest to the polar group of the surfactant molecule appeared to be the most sensitive to the value of the adsorbent surface charge. It is discovered that, upon adsorption of potassium nonanoate from solutions with concentrations of 1.5-3 wt {\%} and pH 6, the surfactant molecules are located in the adsorption layer parallel to the surface. At a higher surface charge, adsorption in the same concentration range occurs mainly on the hydroxyl groups; in this case, adsorbed molecules are arranged mostly along the normal to the surface. At surfactant concentrations much higher than the CMC (10-20{\%}), the values of the chemical shift and relaxation time become closer to those measured in surfactant solutions in the absence of Aerosil.",
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Self-association of potassium nonanoate molecules in aqueous aerosil dispersions:13C NMR data. / Popova, M. V.; Chernyshev, Yu S.

В: Colloid Journal, Том 66, № 5, 01.09.2004, стр. 567-574.

Результат исследований: Научные публикации в периодических изданияхстатья

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