An innovative synthesis approach toward the preparation of structurally defined multiresponsive polymer (co)networks

Abstract

A new and facile synthesis approach employed for the fabrication of multiresponsive polymer conetworks characterized by predefined architecture and composition is described for the first time. The presented methodology involves the crosslinking of well-defined 2-(dimethylamino)ethyl methacrylate (DMAEMA) homopolymers and polyDMAEMA-containing diblock and triblock copolymers prepared by Reversible Addition Fragmentation chain Transfer (RAFT) polymerization, using 1,2-bis-(2-iodoethoxy)ethane (BIEE) as a crosslinker. Unlike other controlled polymerization methods used for the synthesis of well-defined polymer structures, herein the crosslinking step is undemanding since no special synthesis requirements are necessary such as heat and inert conditions. Most importantly it enables the encapsulation of inorganic nanoparticulate systems within the 3-dimensional polymer structures, resulting in the generation of polymer-based nanocomposite (co)networks with structurally defined characteristics. More precisely, the BIEE-crosslinking step is carried out in the presence of pre-formed oleic acid coated magnetite (Fe₃O₄) nanoparticles. The swelling behavior of the resulting (co)networks is investigated in organic and aqueous media at different pHs. Moreover, the magnetic response of the Fe₃O₄-containing (co)networks is studied by means of vibrational sample magnetometry, demonstrating their superparamagnetic behavior at room temperature. This new approach may be easily expanded to generate structurally defined multiblock (and hence multifunctional) copolymer conetworks and organic–inorganic nanocomposites.