DOI: 10.15125/bath-00568
title: Dataset for "Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions"

description: The data set contains ASCII files (tab delimited) for the following:
- Oscillatory frequency sweeps for OCNF dispersions in water/ethanol dispersions with alcohol content varying from 10 to 60 wt% at 10wt% steps.
- Dependence of shear storage modulus and on the ethanol concentration.
- Shear storage modulus values for OCNF hydrogels at 50 wt% of alcohol.
- Dependence of tan delta with the alcohol content on OCNF dispersions.
- Oscillatory frequency sweeps for OCNF dispersions in water/ethanol with OCNF content varying from 0.4 to 1.2 wt% at 0.2 wt% steps.
- Dependence of tan delta on the OCNF concentration for methanol, ethanol, 1- and 2- propanol.
- Dependence of storage modulus on the OCNF concentration for methanol, ethanol, 1- and 2- propanol.
- Flow curves for OCNF dispersions in water/ethanol with alcohol content varying from 00 to 60 wt% at 10wt% steps.
- SAXS curves and fits for OCNF dispersions in water/ethanol dispersions with alcohol content varying from 10 to 50 wt% at 10wt% steps.

Parameters obtained from SAXS data fitting:
- Dependence of Rmax and Rmin on ethanol concentration.
- Dependence of νRPA on ethanol concentration.
- SEM images of 0.8 wt% OCNF dispersions freeze dried and supercritically dried from methanol and ethanol.
description: Rheological measurements were conducted on a stress-controlled Discovery Hybrid Rheometer, Model HR-3 (TA Instruments, USA) equipped with a crosshatched 20 mm parallel plate geometry over a sandblasted lower plate. Temperature was controlled via a Peltier unit (±0.1 °C). A thin layer of low viscosity silicon-oil was added to the edge of the geometry to prevent evaporation. Oscillatory frequency sweeps were conducted at strain (γ) of 0.5% covering the angular frequency of 50 to 0.01 rad/s (Fig 1 and 2 sets) . Flow curves were measured from shear rates of 0.01 to 10 1/s . All experiments were conducted at 25 °C (Fig 3 sets).

Scanning Electron Microscope (SEM) images of cellulose aqueous and alcoholic dispersions (0.8 wt%) were obtained using a JEOL JSM6480LV SEM (Jeol, USA) at 10 kV. Aqueous dispersions were freeze-dried, mounted on adhesive carbon tape and gold sputter-coated prior to imaging of the fibrils. The alcohol dispersions in methanol (100 %) or ethanol (100 %) were sliced into 2 x 2 cm squares, critical point dried from the alcohol and sputter-coated with gold (Fig 4 set).

Small-angle X-ray scattering (SAXS) measurements were conducted at the Diamond Light Source beamline I22 using a PILATUS 2 M (Dectris, Switzerland) detector. The X-ray wavelength used was 1 Å, corresponding to an energy of 12.4 keV, and the accessible q-range was 0.006 to 0.6 1/Å. Data were reduced, and solvent and capillary contributions were subtracted using the Dawn software. Experiments were conducted at room temperature (Fig 5 sets).
description: The SAXS data (Figure 5 set) were fitted using a model of interacting rigid cylinders with elliptical cross sections and uniform scattering length density. 
The fitting parameters for the form factor of the fibrils are the major and minor radii of the cross-section of the cylinders, Rmax and Rmin respectively, and the length of the fibrils, L. Polydispersity of the cross section was not modelled. The effect of interactions on the scattering was calculated using the PRISM model, with the parameter νRPA , proportional to the concentration of cylinders, describing the strength of the interactions between the cylinders (the local excluded volume radius around each site being neglected for weak interactions).
description: Further relevant documentation may be found in the following resources.

   da Silva, M. A., Calabrese, V., Schmitt, J., Celebi, D., Scott, J. L., and Edler, K. J.,  2018.   Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions.    Soft Matter, 14(45), 9243-9249.  Available from: https://doi.org/10.1039/c8sm01815d.