(617h) Ultrastretchable, Tough and Superabsorbent Hydrogel with Spherical Polyelectrolyte Brushes As Macromolecular Crosslinkers

Ultrastretchable,
Tough and Superabsorbent Hydrogel with Spherical Polyelectrolyte Brushes as
Macromolecular Crosslinkers

Yu
Cang, Rui Zhang, Xuhong Guo

State Key Laboratory of
Chemical Engineering, East China University of Science and Technology, 130 Meilong
Road, Shanghai 200237, China

Abstract: Hydrogels were three-dimension
networks of chemical or physical crosslinked polymer chains. The adequate
mechanical properties were necessary for applications of hydrogels, which have
been important characteristics to evaluate their performance. Many strategies
were devoted to robust hydrogel synthesis, such as introduction the coexisting
network to form double-network hydrogel, using inorganic/macromolecular
crosslinkers to form homogenous networks. All these methods could improve the
mechanical properties by increasing the crosslinked density of network, but at
expense of water absorbency property. We used spherical polyelectrolyte brushes
(SPBs) as crosslinkers to form ionic hydrogel which was tough and could absorb
considerate water simultaneously. The polymer chains of SPBs was modified with
thiol groups and covalent bonded with monomer via Michael-type addition
reaction. The SPBs hydrogel was enough robust to sustain high level compression
and stretched up to more than 40 times their original length. Besides, the
water absorbency was surprisingly large that the swelling ratio reached above
3000 (Figure 1). The ideal combination of mechanical properties and water
absorbency would open a new scope for hydrogels.

Keywords: spherical
polyelectrolyte brushes, hydrogel, superabsorbent,
crosslinker

Figure 1. (A) Optical images showing the
hydrogel with high mechanical properties. (B) The elongation. elastic modulus and tensile test of hydrogel with different
concentration of monomers and crosslinkers.