Self-healable, Tough, and Ultra Stretchable Nanocomposite Hydrogels Based on Reversible Polyacrylamide/Montmorillonite Adsorption
作者：Guorong Gao, Gaolai Du, Yuanna Sun, and Jun Fu
關鍵字：nanocomposite hydrogels, tough, stretchable, self-heal, montmorillonite
論文來源：期刊
具體來源：ACS Applied Materials and Interfaces, DOI: 10/1021/acsami.5b00704
發表時間：2015年
Nanocomposite hydrogels with unprecedented
stretchability, toughness, and self-healing have been developed by in situ
polymerization of acrylamide with the presence of exfoliated montmorillonite
(MMT) layers as non-covalent crosslinkers. The exfoliated MMT clay
nanoplatelets with high aspect ratio, as confirmed by TEM and XRD results, are
well dispersed in the polyacrylamide matrix. Strong polymer/MMT
interaction was confirmed by Fourier transform infrared spectroscopy (FTIR) and differential scanning
calorimetry (DSC). The effective crosslink densities of these
hydrogels are estimated in the range of 2.2 – 5.7 mol m–3. Uniaxial
tensile tests showed a very high fracture elongation up to 11 800 % and a fracture toughness
up to 10.1 MJ m–3. Cyclic
loading-unloading tests showed remarkable hysteresis, which indicates energy
dissipation upon deformation. Residual strain after
cyclic loadings could be recovered under mild conditions, with the recovery
extent depending on clay content. A mechanism based on
reversible desorption/adsorption of polymer chains on clay platelets surface is discussed. Finally, these nanocomposite
hydrogels are demonstrated to fully heal by dry-reswell treatments.