Liu Xinyu, Niu Xiaofeng, Fu Zhinan, Liu Liqun, Bai Shengyu, Wang Jie, Li Li, Wang Yiming, Guo Xuhong
State Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Soft Matter. 2020 Sep 23;16(36):8394-8399. doi: 10.1039/d0sm01132k.
LAPONITE® 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® 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® sheets were effectively reduced due to the adsorption of PAA onto the positively charged edges of the LAPONITE® sheets, thereby accelerating the dispersion of the LAPONITE® sheets in water. On this basis, a series of polyacrylamide (PAAm) hydrogels with a high content of LAPONITE® sheets was prepared, showing excellent tensile strength, stretchability, and anti-fatigue properties. This study will be beneficial for the preparation of LAPONITE®-based nanocomposite hydrogels bearing excellent mechanical properties for new applications.
LAPONITE®片材已被广泛用于制备具有诱人应用前景的坚韧纳米复合水凝胶；然而，由于纳米片之间的静电相互作用，它们在水性介质中的分散性较差，这显著限制了纳米复合水凝胶机械性能的进一步提高。在此，我们展示了一种简单的方法，可显著加速LAPONITE®片材在水中的分散，进而进一步提高所得纳米复合水凝胶的机械性能。加入聚丙烯酸（PAA）后，由于PAA吸附在LAPONITE®片材带正电的边缘上，LAPONITE®片材之间的静电相互作用有效降低，从而加速了LAPONITE®片材在水中的分散。在此基础上，制备了一系列含有高含量LAPONITE®片材的聚丙烯酰胺（PAAm）水凝胶，其表现出优异的拉伸强度、拉伸性和抗疲劳性能。本研究将有助于制备具有优异机械性能的基于LAPONITE®的纳米复合水凝胶，以用于新的应用。
