International audienceThis review intends to present different aspects concerning clay/polymer nanocomposites produced by heterophase polymerization in aqueous media. This paper highlights the ability of miniemulsion polymerization to produce clay/polymer nanoparticles with tailored nanostructures. Indeed, this polymerization route enables the synthesis of composite nanoparticles with the clay platelets located either on the surface of the polymer particle or embedded inside the polymer particle. A focus is given on the influence of these nanostructures on the properties of the final material through a direct comparison of the composites obtained after water evaporation from these structured nanoparticles. indeed, the film obtained from the film forming process of these nanoparticles present significantly different nanostructures and exhibit totally different mechanical behaviours and water uptakes. By comparing experimental results and modeling approaches, it is demonstrated that their properties are clearly related to the clay dispersion and contacts. It is also evidenced that the main drawback of miniemulsion from the coating application point of view, is the large water uptake promoted by the surfactant presence whose localization is strongly influenced by nanostructuration. This stresses the need for the further development of surfactant free miniemulsion polymerization using advantageously the clay presence to stabilize the emulsion

Reversible addition−fragmentation chain transfer (RAFT) polymerization of the reactive monomer γ-methacryloxypropyltrimethoxysilane (γMPS) mediated by 2-cyanoprop-2-yl dithiobenzoate (CPDB) has been studied in dioxane using 2,2‘-azobis(isobutyronitrile) (AIBN) as initiator. Conditions were optimized for a polymerization temperature of 80 °C, and controlled PγMPS chains (up to M n = 40 000 g mol-1) exhibiting low polydispersity indexes (PDI < 1.3) were synthesized. Their characterization by matrix-assisted laser desorption ionization time-of-flight (MALDI-ToF) mass spectrometry showed that the expected structure was obtained although degradation of the dithiobenzoate chain end occurred. Syntheses of block copolymers based on γMPS and methyl methacrylate (MMA) were performed starting from either the PγMPS (M n = 32 100 g mol-1, PDI = 1.16, PMMA calibration) or the PMMA block (M n = 21 000 g mol-1, PDI = 1.14). The success of the block copolymerization was showed by the shift toward higher molar mass of the size exclusion chromatography (SEC) chromatograms recorded before and after block copolymerization. Proton NMR analyses of P(MMA-b-γMPS) allowed to calculate the molar mass of the PγMPS blocks (17 400 g mol-1) which agreed with the targeted one (18 150 g mol-1).