Dynamics of adsorption of CTAB-Silica nanoparticle complexes: New experiments and modeling approach

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Amin Jafarlou - , University of Tehran (Author)
  • Aliyar Javadi - , University of Tehran, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), TUD Dresden University of Technology (Author)
  • Reinhard Miller - , Technische Universität Darmstadt (Author)
  • Kerstin Eckert - , Chair of Transport Processes at Interfaces, Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Author)

Abstract

The adsorption dynamics of silica nanoparticles (NP) and cetyltrimethylammonium bromide (CTAB) complexes is studied via dynamic surface properties characterization by the drop Profile Analysis Tensiometry (PAT). Considering the hypothesis that a nanoparticle with a certain number of attached surfactant molecules can be considered as a unified surface-active complex, the equilibrium surface tension for fixed CTAB/NP mixing ratios were considered to construct respective adsorption isotherms. The results can be well described by the Frumkin adsorption model. The fitting parameters of the Frumkin model for different mixing ratios demonstrate that complexes with higher mixing ratios occupy less space at the interface and show weaker interaction with each other. Also, the Ward and Tordai equation was fitted to the dynamic surface tension data for each ratio. The results show that by increasing the mixing ratio the adsorption of complexes tends toward a diffusion-controlled mechanism. On the other hand, for lower mixing ratios, the adsorption is affected by adsorption/desorption barriers so that a mixed diffusion-kinetic-controlled mechanism is recognized and discussed.

Details

Original languageEnglish
Article number127448
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume629
Publication statusPublished - 20 Nov 2021
Peer-reviewedYes

Keywords

Keywords

  • CTAB silica complexes, Diffusion/kinetics controlled adsorption, Drop profile analysis tensiometry, Dynamics of adsorption, Stokes-Einstein equation, Surfactant-nanoparticle interactions