Thermoresponsive Nanocellulose Hydrogels with Tunable
Mechanical Properties
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Abstract
Cellulose microfibrils physically
bound together by soft hemicellulose
chains form the scaffolding that makes plant cell walls strong. Inspired
by this architecture, we designed biomimetic thermoreversible hydrogel
networks based on reinforcing cellulose nanocrystals (CNC) and thermoresponsive
methylcellulose (MC). Upon dissolving MC powder in CNC aqueous dispersions,
viscoelastic dispersions were formed at 20 °C, where the storage
modulus (<i>G</i>′) is tunable from 1.0 to 75 Pa
upon increasing the CNC concentration from 0 to 3.5 wt % with 1.0
wt % MC. By contrast, at 60 °C a distinct gel state is obtained
with <i>G</i>′ ≫ <i>G</i>″, <i>G</i>′ ∼ ω<sup>0</sup>, with an order of
magnitude larger <i>G</i>′ values from 110 to 900
Pa upon increasing the CNC concentration from 0 to 3.5 wt % with constant
1.0 wt % MC, due to the physical cross-links between MC and CNCs.
Therefore, simply mixing two sustainable components leads to the first
all-cellulose thermoreversible and tunable nanocellulose-based hydrogels