Chemically crosslinked hydrogels have improved
mechanical strength than their physically crosslinked
counterparts [14]. However, crosslinking reactions present
some disadvantages regarding coupling agents, catalysts or
photoinitiators requirements that can affect the biocompatibility
of the final material [15]. The Diels–Alder (DA)
reaction can be employed for the preparation of chemically
crosslinked hydrogels without suffering from those drawbacks,
since it is free from side reactions and does not require
the participation of any additives. The DA
cycloaddition is a thermoreversible coupling between a
diene and a dienophile, which allows the recovery of the
starting reagents by heating [16]. The interest in exploiting
the DA reaction with furan compounds grounds in their
renewable nature and their pronounced dienic character
which favor the reaction in terms of yield and kinetics
[16]. Moreover, some authors reported the acceleration of
the reaction rate when water is used as solvent [17,18].
Maleimides are the most commonly employed dienophiles
because of their high reactivity and the broad range of
structural possibilities which can be offered by the substituent
at the nitrogen atom [19]. The ensuing materials
could as reversible coatings [20], biomaterials [21], hydrogels
for tissue engineering [15], phase-change materials
[22] and self-healing materials [23].
Hydrogels have been prepared by the