A facile approach to obtain highly tough and stretchable LAPONITE®-based nanocomposite hydrogels

LAPONITE (R) sheets have been widely used for the preparation of tough nanocomposite hydrogels for enticing applications; however, their inferior dispersion in aqueous media resulting from electrostatic interactions between the nanosheets remarkably limits further improvements in the mechanical performances of the nanocomposite hydrogels. Here, we show a simple approach to dramatically accelerate the dispersion of LAPONITE (R) sheets in water, and in turn further improve the mechanical performances of the resulting nanocomposite hydrogels. Upon addition of poly(acrylic acid) (PAA), the electrostatic interactions between the LAPONITE (R) sheets were effectively reduced due to the adsorption of PAA onto the positively charged edges of the LAPONITE (R) sheets, thereby accelerating the dispersion of the LAPONITE (R) sheets in water. On this basis, a series of polyacrylamide (PAAm) hydrogels with a high content of LAPONITE (R) sheets was prepared, showing excellent tensile strength, stretchability, and anti-fatigue properties. This study will be beneficial for the preparation of LAPONITE (R)-based nanocomposite hydrogels bearing excellent mechanical properties for new applications.