This was mostly driven by a pursuit of hydrogels with improved mechanical properties. 1 Introduction Since the pioneering work 1 by the Haraguchi group a decade ago, nanocomposite hydrogels (NCHs) have generated significant interest. ![]() The composition of the initiating system influences the number of formed self-crosslinks. There is evidence of self-crosslinking of polymer chains during acrylamide polymerisation at high monomer concentration. From the analysis of the water state in NCH and hydrogels prepared with and without an organic cross-linker, it was concluded that clay platelets did not form covalent bonds with polymer molecules but contributed to the formation of a physical network. This trend is attributed to the increase in the cross-linking degree. We further show that activator-dominated systems tend to produce hydrogels with higher storage modulus and lower water intake. The molar ratio of the persulphate initiator to tertiary amine activator affects the polymerisation kinetics, morphology and mechanical properties of the hydrogels. A unique, complementary combination of real-time dynamic rheology and pulsed NMR/MRI has been used to study the influence of the composition of a redox initiating system on the gelation process and hydrogel properties. Here, we demonstrate that the properties of NCHs significantly vary depending on initiating conditions used for hydrogel synthesis via in situ polymerisation in solutions of high monomer concentrations (above 1 mol L −1). ![]() The central intent of many research studies in the field of NCHs conducted so far was to change hydrogel properties with the introduction of various clays and variation of the clay content. Free-radical polymerisation of acrylamide derivatives in the presence of exfoliated clay platelets has recently emerged as a new technique for the synthesis of strong and tough nanocomposite hydrogels (NCHs) with a unique hybrid organic/inorganic network structure.
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