Synthesis and characterization of robust double-networks based on end-linked, pH-responsive first networks

Fragile, end-linked hydrophilic tertiary amine based methacrylate (first) networks were mechanically reinforced using the double-network principle, via the introduction of a polyacrylamide second network. Reinforcement with the second network was performed on the first network both at its neutral and fully ionized states. Although significantly more polyacrylamide was introduced in to the ionized first networks (higher aqueous swelling degrees), better mechanical properties were also exhibited by the double-networks (DN) comprising neutral first networks. All DNs presented better mechanical properties than the methacrylate first networks, with the DNs based on neutral first networks displaying high compressive strain at break, and those based on ionized first networks displaying higher modulus in compression and higher fracture energy. (C) 2015 Elsevier Ltd. All rights reserved.