Layered double hydroxides: Efficient fillers for waterborne nanocomposite films

• Preparation of waterborne latex/LDH based nanocomposite films
• The content of the LDH into the films was varied from 2.5 vol% to 15 vol%.
• SEM and TEM showed the formation of a cellular network.
• Above 2.5 vol% LDH layers form a percolating mechanical network with a very large reinforcement efficiency.

Using Layered double hydroxides (LDH) nanoparticles and film-forming latexes, waterborne nanocomposite films were produced by simply a heterocoagulation and solvent casting process. Self-standing and transparent films with LDH contents from 2.5 to 15 vol% were prepared. The structure, microstructure and mechanical behavior were thoroughly investigated by powder X-ray diffraction (PXRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), scanning electron microscopy (FIB–SEM) and dynamic mechanical analysis (DMA). Favorable electrostatic interactions between pristine LDH and the latex ensured a good dispersion of the bidimensional LDH platelets in the films. Above a certain content of LDH, the formation of a well-defined cellular LDH network following the starting latex morphology was observed. Such a percolating microstructure induces a large mechanical reinforcement significant of a mechanical percolation behavior.

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