Lutz-Bueno V, Diaz A, Wu T, Nyström G, Geiger T, Antonini C. Hierarchical Structure of Cellulose Nanofibril-Based Foams Explored by Multimodal X-ray Scattering.
Biomacromolecules 2022;
23:676-686. [PMID:
35194986 PMCID:
PMC8924866 DOI:
10.1021/acs.biomac.1c00521]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
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Structural characterization
techniques are fundamental to correlate
the material macro-, nano-, and molecular-scale structures to their
macroscopic properties and to engineer hierarchical materials. Here,
we combine X-ray transmission with scanning small- and wide-angle
X-ray scattering (sSWAXS) to investigate ultraporous and lightweight
biopolymer-based foams using cellulose nanofibrils (CNFs) as building
blocks. The power of multimodal sSWAXS for multiscale structural characterization
of self-assembled CNFs is demonstrated by spatially resolved maps
at the macroscale (foam density and porosity), at the nanoscale (foam
structural compactness, CNF orientation in the foam walls, and CNF
packing state), and at the molecular scale (cellulose crystallite
dimensions). Specifically, we compare the impact of freeze–thawing–drying
(FTD) fabrication steps, such as static/stirred freezing and thawing
in ethanol/water, on foam structural hierarchy spanning from the molecular
to the millimeter scale. As such, we demonstrate the potential of
X-ray scattering imaging for hierarchical characterization of biopolymers.
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