Fig 1.
A comparison of the Raman spectra of (a) GO with cGO crosslinked with Ca at 24, 34 and 55°C, and (b) GO with cGO crosslinked with Ca, Zn and Sr at 24°C.
Fig 2.
Results in wt.% for GO and cGO crosslinked with Ca2+, Zn2+ and Sr2+.
Fig 3.
Field emission scanning electron microscopy.
Images at a magnification of 50000 of (a) GO and cGO crosslinked with (b) Ca2+, (c) Zn2+ and (d) Sr2+ synthesised at 24°C.
Fig 4.
High-resolution transmission electron microscopy.
Micrographs at two magnifications (a&b) with STEM dark field (c) of GO crosslinked with Zn2+ and uncrosslinked GO nanosheets (d).
Fig 5.
Morphology and differential scanning calorimetry.
Confocal microscopy of (a) GO/Alg, (b&d) cGO/Alg, (c) DSC thermograms on heating of these samples at 10°C/min and (e) their morphology after swelling in water for 3 hours.
Fig 6.
Temperature dependence of the storage modulus (solid symbols) and the loss tangent (open symbols) of cGO/Alg (◯) and GO/Alg (◇). Only one point out of ten is plotted to obtain a clearer representation.
Fig 7.
Fourier transform infrared spectroscopy.
Spectra of cGO/Alg and GO/Alg from 650 to 4000 cm-1.