Hydrogels were prepared at high solid contents (70–100
g/L)
with cellulose nanocrystals (CNC) and very short xyloglucans (XGs).
At 70 g/L, CNCs form cholesteric liquid crystals regularly spaced
by a distance of 30 nm. This structure was preserved after adsorption
of XG with a molar mass (Mw) of 20,000
g/mol (XG20) but was lost at 40,000 g/mol (XG40). Rheological measurements
discriminated domains where an increasing Mw from XG20 to XG40 gave rise to drastic changes in storage moduli
(on 3 orders of magnitude). At 40,000 g/mol, transient systems were
obtained and a re-entrant glass–gel–glass transition
was observed with increasing XG concentrations. This was interpreted
in terms of the length and stiffness of the chain in relation to the
inter-CNC distance. Liquid-to-glass-to-gel transitions were attributed
to an XG adsorption type according to train or trail conformations
or interconnected structures. Such tunable properties may further
have implications on the in vivo role of XG during cell wall extension.