Surfactant induced gelation of TEMPO-oxidized cellulose nanofibril dispersions probed using small angle neutron scattering

Julien Schmitt, Vincenzo Calabrese, Marcelo A. Da Silva, Kazi M.Z. Hossain, Peixun Li, Najet Mahmoudi, Robert M. Dalgliesh, Adam L. Washington, Janet L. Scott, Karen J. Edler

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3 Citations (SciVal)

Abstract

In this work, we studied TEMPO-oxidized cellulose nanofibril (OCNF) suspensions in the presence of diverse surfactants. Using a combination of small angle neutron scattering (SANS) and rheology, we compared the physical properties of the suspensions with their structural behavior. Four surfactants were studied, all with the same hydrophobic tail length but different headgroups: hexaethylene glycol mono-n-dodecyl ether (C12EO6, nonionic), sodium dodecyl sulfate (SDS, anionic), cocamidopropyl betaine (CapB, zwitterionic), and dodecyltrimethylammonium bromide (DTAB, cationic). Contrast variation SANS studies using deuterated version of C12EO6 or SDS, or by varying the D2O/H2O ratio of the suspensions (with CapB), allowed focusing only on the structural properties of OCNFs or surfactant micelles. We showed that, in the concentration range studied, for C12EO6, although the nanofibrils are concentrated thanks to an excluded volume effect observed in SANS, the rheological properties of the suspensions are not affected. Addition of SDS or CapB induces gelation for surfactant concentrations superior to the critical micellar concentration (CMC). SANS results show that attractive interactions between OCNFs arise in the presence of these anionic or zwitterionic surfactants, hinting at depletion attraction as the main mechanism of gelation. Finally, addition of small amounts of DTAB (below the CMC) allows formation of a tough gel by adsorbing onto the OCNF surface.

Original languageEnglish
Article number034901
JournalJournal of Chemical Physics
Volume158
Issue number3
Early online date17 Jan 2023
DOIs
Publication statusPublished - 21 Jan 2023

Bibliographical note

Funding Information:
The authors thank EPSRC for funding this project (Grant No. EP/N033310/1). Dr. Vincenzo Calabrese thanks the University of Bath for PhD studentship funding. Experiments at the ISIS Pulsed Neutron and Muon Source were supported by beam time allocations for Larmor from the Science and Technology Facilities Council under Proposal No. RB1720220. Measurements on CEO systems were made on Sans2D (Proposal No. RB1720206). 12 6

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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