Zheng Cao, Yuyuan Chen, Qianpeng Zhang, Yanping Xia, Gang Liu, Dun Wu, Wenzhong Ma, Junfeng Cheng, Chunlin Liu
March 2, 2018
The polyanion polystyrene sulfonate (PSS), the polycation poly (allylamine hydrochloride) (PAH), and the anionic poly (N-isopropylacrylamide-co-acrylic acid) [P(NIPAM-co-AA)] microgels were self-assembled onto the polyethylene imine (PEI) adsorbed gold surfaces of quartz crystal microbalance (QCM) because of the electrostatic attractions. The interactions of various metal particles including Ca 2+ , Bi 3+ , Cu 2+ , Zn 2+ , Ni 2+ , Sn 2+ , Co 2+ , and Cd 2+ with the obtained PEI/PSS/PAH/microgel layer in aqueous solutions were evaluated by QCM. The PEI/PSS/PAH/Microgel covered QCM sensor demonstrates the lowest detection limit of 0.1 ppm in aqueous solutions and the obviously linear connection between the frequency response and Ni 2+ concentration from 0.1 to 20 ppm, which is due to the complexation of Ni 2+ with the carboxyl groups of microgels. Atomic force microscopy (AFM) was used to reveal the morphology and stability of the self-assembled polyelectrolyte/microgel layer before and after adsorbing heavy metal ions. These self-assembled materials of polyelectrolyte/microgel layer will be helpful for manufacturing ion-selective materials for separation and identification purposes.