Spin Diffusion Transfer Difference (SDTD) NMR: An advanced method for the characterisation of water structuration within particle networks

Valeria Gabrielli, Agne Kuraite, Marcelo Alves da Silva, Karen J. Edler, Jesús Angulo, Ridvan Nepravishta, Juan C. Muñoz-García, Yaroslav Z. Khimyak

Research output: Contribution to journalArticlepeer-review

Abstract

Hypothesis: The classical STD NMR protocol to monitor solvent interactions in gels is strongly dependent on gelator and solvent concentrations and does not report on the degree of structuration of the solvent at the particle/solvent interface. We hypothesised that, for suspensions of large gelator particles, solvent structuration could be characterised by STD NMR when taking into account the particle-to-solvent 1H– 1H spin diffusion transfer using the 1D diffusion equation. Experiments: We have carried out a systematic study on effect of gelator and solvent concentrations, and gelator surface charge, affecting the behaviour of the classical STD NMR build-up curves. To do so, we have characterised solvent interactions in dispersions of starch and cellulose-like particles prepared in deuterated water and alcohol/D 2O mixtures. Findings: The Spin Diffusion Transfer Difference (SDTD) NMR protocol is independent of the gelator and solvent concentrations, hence allowing the estimation of the degree of solvent structuration within different particle networks. In addition, the simulation of SDTD build-up curves using the general one–dimensional diffusion equation allows the determination of minimum distances (r) and spin diffusion rates (D) at the particle/solvent interface. This novel NMR protocol can be readily extended to characterise the solvent(s) organisation in any type of colloidal systems constituted by large particles.

Original languageEnglish
Pages (from-to)217-227
Number of pages11
JournalJournal of Colloid and Interface Science
Volume594
Early online date9 Mar 2021
DOIs
Publication statusPublished - 15 Jul 2021

Keywords

  • Hydrogel
  • Saturation transfer difference NMR
  • Solvation properties
  • Spin diffusion

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