Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions

DOI: 10.1039/C8SM01815D

Authors: Marcelo A. Da Silva (University of Bath) , Vincenzo Calabrese (University of Bath) , Julien Schmitt (University of Bath) , Duygu Celebi (University of Bath) , Janet L. Scott (University of Bath) , Karen J. Edler (University of Bath)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Soft Matter

State: Published (Approved)
Published: October 2018
Diamond Proposal Number(s): 16364

Abstract: Solvent-induced physical hydrogels of TEMPO-oxidized cellulose nanofibrils (OCNFs) were obtained from aqueous/alcoholic dispersions of fibrils in lower alcohols, namely, methanol, ethanol, 1-propanol and 2-propanol. The sol-gel transition occurs above a critical alcohol concentration of ca. 30 wt% for all alcohols tested. The rheological properties of the hydrogels depend on the nature of the alcohol: for ethanol, 1-propanol and 2-propanol the magnitude of the shear storage modulus follows the alcohol hydrophilicity, whilst methanol produce the weakest gels in the group. Above a second critical concentration, ca. 60 wt% alcohol, phase separation is observed as the gels undergo syneresis. Analysis of small-angle X-ray scattering data show that the OCNFs may be modelled as rigid rods. In the presence of lower alcohols, attractive interactions between nanofibrils are present and, above the alcohol concentration leading to gelation, an increase of OCNF cross-section is observed, suggesting alcohol induced aggregation of nanofibrils.

Subject Areas: Chemistry, Materials


Instruments: I22-Small angle scattering & Diffraction

Added On: 29/10/2018 11:13

Documents:
c8sm01815d.pdf

Discipline Tags:

Soft condensed matter physics Chemistry Materials Science Organic Chemistry Polymer Science

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)