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Download fileComposite Hydrogels with Tunable Anisotropic Morphologies and Mechanical Properties
journal contribution
posted on 14.04.2016, 00:00 authored by Mokit Chau, Kevin J. De France, Bernd Kopera, Vanessa R. Machado, Sabine Rosenfeldt, Laura Reyes, Katelyn J. W. Chan, Stephan Förster, Emily D. Cranston, Todd Hoare, Eugenia KumachevaFabrication
of anisotropic hydrogels exhibiting direction-dependent
structure and properties has attracted great interest in biomimicking,
tissue engineering, and bioseparation. Herein, we report a freeze-casting-based
fabrication of structurally and mechanically anisotropic aerogels
and hydrogels composed of hydrazone cross-linked poly(oligoethylene
glycol methacrylate) (POEGMA) and cellulose nanocrystals (CNCs). We
show that, by controlling the composition of the CNC/POEGMA dispersion
and the freeze-casting temperature, aerogels with fibrillar, columnar,
or lamellar morphologies can be produced. Small-angle X-ray scattering
experiments show that the anisotropy of the structure originates from
the alignment of the mesostructures, rather than the CNC building
blocks. The composite hydrogels show high structural and mechanical
integrity and a strong variation in Young’s moduli in orthogonal
directions. The controllable morphology and hydrogel anisotropy, coupled
with hydrazone cross-linking and biocompatibility of CNCs and POEGMA,
provide a versatile platform for the preparation of anisotropic hydrogels.