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. 2023 Feb 1;123(5):1925–2015. doi: 10.1021/acs.chemrev.2c00611

Figure 25.

Figure 25

Analysis of cellulose–water interactions by NMR (a–c), IR (d), and dielectric (e,f) spectroscopy, and by spectroscopic ellipsometry (SE, g-i) and surface plasmon resonance spectroscopy (j-l): (a) Solid echo 2H NMR spectra of dried and wet cellulose at 210 and 300 K. Transition of the typical Pake pattern (slow 2H exchange) to narrow Lorentzian peaks (fast 2H exchange).1102 (a) Modified with permission fromref (1102). Copyright 1996 American Chemical Society. (b) 2H MAS NMR spectra of hydrated and redried MCC in full scale (top) and magnified (bottom) illustrating the signals arising from mobile water (intense central peak) and from the other deuterium-containing sample fractions (SSBs spread over a broad frequency range).270 (b) Modified under the terms of CC-BY from ref (270). Copyright 2017 Royal Society of Chemistry. (c) Comparison of experimental and simulated distributions of 13C T1 relaxation times, normalized to the same value, for C6.995 (c) Reproduced with permission from ref (995). Copyright 2019 American Chemical Society. (d) Static FT-IR spectra of spruce cellulose at increasing relative humidity with deuterium vapor.204 (d) Modified with permission from ref (204). Copyright 2006 Springer Nature. (e) Dielectric site model of a polysaccharide repeating unit. (f) Principal structure of a dielectric loss spectrum of a wet polysaccharide.1104 (e,f) Adapted with permission from ref (1104). Copyright 2001 Elsevier. (g–i) SE adsorption isotherms of (g) 5, (h) 10, and (i) 20 g L–1 CNC thin films. Hysteresis of swelling is a measure of the difference between the integrated areas below the adsorption and desorption isotherms.271 (g–i) Adapted with permission from ref (271). Copyright 2015 American Chemical Society. (j) Swelling profiles of highly sulfated CNC (HS-CNC) films measured by SPR. Curves are normalized to the angular shift immediately following NaCl solution addition. (k) Calculated volume of water within the CNC films (LS-CNC, low sulfate content CNC; CAT-CNC, cationic CNC) in various concentrations of NaCl after 30 min of swelling determined from SPR profiles. Film porosity (the volume of air in the films initially) is taken as 20%. (l) Diffusion constants calculated for water in CNC films measured from SPR swelling experiments in NaCl solutions.283 (j–l) Adapted with permission from ref (283). Copyright 2017 American Chemical Society.