Surface functional group composition as obtained from the deconvolution of the C 1

a<p>The binding energy for each signal is given with variation seen between different sample.</p

FT-IR spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, and (d) SNC_HCl,7.

<p>FT-IR spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, and (d) SNC_HCl,7.</p

Zeta potential of SNC_H2SO4,7 (gray color) and SNC_HCl,7 (white color) suspensions at pH 6.5 and 10.6 placed for 2 h and 48 h, respectively.

<p>Data are represented as the mean ± standard deviation (n = 3).</p

Elemental surface composition (atomic %) and oxygen to carbon ratio of starch, HCl- and H₂SO₄-hydrolyzed SNC.

<p>Elemental surface composition (atomic %) and oxygen to carbon ratio of starch, HCl- and H₂SO₄-hydrolyzed SNC.</p

The high-resolution C 1 s deconvoluted XPS spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, (d) SNC_HCl,7.

<p>The high-resolution C 1 s deconvoluted XPS spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, (d) SNC_HCl,7.</p

General XPS spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, and (d) SNC_HCl,7.

<p>General XPS spectra of (a) WMS, (b) SNC_H2SO4,3, (c) SNC_H2SO4,7, and (d) SNC_HCl,7.</p

Formation of sulfate esters and adsorption of formic and levulinic acids on the surface of SNC (a: Formation of sulfate ester, b: adsorption of formic and levulinic acids).

<p>Formation of sulfate esters and adsorption of formic and levulinic acids on the surface of SNC (a: Formation of sulfate ester, b: adsorption of formic and levulinic acids).</p

TEM pictures and sedimentation properties of HCl (a and b) and H₂SO₄ (c and d) hydrolyzed SNC suspensions after 2 h and 48 h.

<p>TEM pictures and sedimentation properties of HCl (a and b) and H₂SO₄ (c and d) hydrolyzed SNC suspensions after 2 h and 48 h.</p

The high-resolution S 2p deconvoluted XPS spectra of (e) WMS, (f) SNC_H2SO4,3, (g) SNC_H2SO4,7, and (h) SNC_HCl,7.

<p>The high-resolution S 2p deconvoluted XPS spectra of (e) WMS, (f) SNC_H2SO4,3, (g) SNC_H2SO4,7, and (h) SNC_HCl,7.</p

TGA and the derivative TGA curves of CMS and microgels for various degrees of substitution (DS).

<p>a, b, and c are CMS of DS 0.31, 0.67, and 0.95, respectively. A, B, and C are microgels of DS 0.31, 0.67, and 0.95, respectively.</p