The formation of the hydrogel poly(N-isopropylacrylamide)–clay (LAPONITE®) by redox polymerization was investigated, and the main factors governing the gel build-up were determined. The significant effect of the redox initiating system ammonium peroxodisulfate (APS) and tetramethylethylenediamine (TEMED) on gel formation and structure was established, making it possible to control the structure of the gel. Moreover, the pre-reaction stage involving the quality of the clay exfoliation in an aqueous suspension and the interaction of reaction components with the clay play a role in controlling the polymerization and gel structure. The molecular and phase structure evolution during polymerization was followed in situ by the following independent techniques: Fourier transform infrared spectroscopy (FTIR), chemorheology, small-angle X-ray scattering (SAXS) and ultraviolet-visible spectroscopy (UV/Vis). The combination of these methods enabled us to describe in detail particular progress stages during the gel formation and determine the correlation of the corresponding processes on a time and conversion scale. The mechanism of gel formation was refined based on these experimental results.

This work addresses the use of ionic liquids (ILs) as additives for formation of epoxy-silica nanocomposites, via the simultaneous sol–gel process and epoxy network build-up. The application of different methylimidazolium based ILs allows controlling the silica structure and modifying interphase interaction, thus producing hybrids with diverse morphologies and improved mechanical properties. Both the anionic and cationic components of the ILs affected the hybrid formation and the final properties. The application of 1-decyl-3-methylimidazolium tetrafluoroborate ionic liquid together with HCl as an acid catalyst promotes both hydrolysis and condensation in the sol–gel process as well as the self-assembly ordering of the IL. This system produces a very fine hybrid morphology with well dispersed silica nanodomains and a significantly increased rubbery modulus due to physical crosslinking by the ordered domains of decyl-substituents.

Understanding the organic–inorganic interphases of hybrid materials allows structure and properties control for obtaining new advanced materials. Lately, the use of ionic liquids (ILs) and poly(ionic liquids) (PILs) allowed structure control from the first sol-gel reaction steps due to their anisotropy and multiple bonding capacity. They also act as multifunctional compatibilizing agents that affect the interfacial interactions in a molecular structure-dependent manner. Thus, this review will explore the concepts and latest efforts to control silica morphology using processes such as the sol-gel, both in situ and ex situ of polymer matrices, pre-polymers or polymer precursors. It discusses how to control the polymer–filler interphase bonding, highlighting the last achievements in the interphase ionicity control and, consequently, how these affect the final nanocomposites providing materials with barrier, shape–memory and self-healing properties.

High performance shape memory (SM) epoxy–silica nanocomposites have been synthesized. The structure of the corresponding SM polymer was designed on the basis of the determined relationships between structure, mechanical properties and SM performance. The recovery stress, as a crucial SM property of high performance systems, is governed by the material toughness while the efficiency of the SM performance is controlled by morphological homogeneity and viscoelastic behaviour of the polymer as well as by experimental conditions of the SM procedure. The nanocomposites were prepared by in situ generation of nanosilica in the epoxy matrix. A non-aqueous sol–gel procedure was applied and the ionic liquid (IL) was used in the synthesis as a multifunctional agent controlling morphology and mechanical properties. The effect of nanosilica, IL, crosslinking density of the epoxy network, physical crosslinking as well as the application of the concept of bimodal networks on SM performance was evaluated and discussed. Based on the knowledge of the corresponding relationships and structural effects the SM nanocomposite was synthesized showing the high recovery stress σ_r = 3.9 MPa or high deformability ε_b = 103%. The study contributed to the better understanding of the SM behaviour of polymers.

Imidazolium ionic liquids (ILs) have the capacity to exert multiple functions as additives for the formation of epoxy-silica nanocomposites, via the simultaneous sol–gel process and epoxy network build-up. This study addresses the effect of ILs on the reinforcement of tensile properties in rubbery epoxy-silica nanocomposites, allowing property tailoring. The use of ILs together with the coupling agent 3-glycidyloxypropyltrimethoxysilane (GTMS) created a synergic action between physical and chemical interfacial bonding, enabling an increase in toughness without a considerable loss of stiffness. The best tensile property balance was obtained with IL 1-triethylene glycol monomethyl ether-3-methylimidazolium methanesulfonate and GTMS. The rubbery nanocomposite produced was remarkably both stiffer and tougher than the unmodified epoxy-silica system, displaying ca. 6 times higher modulus and tensile strength as well as more than 10 times higher energy to break.