原子力显微镜分析聚二甲基二烯丙基铵盐的吸附和絮凝行为:反离子的影响

通过对聚二甲基二烯丙基氯化铵(PDADMAC)改性得到了高分子量的聚二甲基二烯丙基硝酸铵(PDADMANO₃)和聚二甲基二烯丙基硫酸铵(PDADMASO₄).通过电导率,比浓粘度,原子力显微镜,以及高岭土悬浊液絮凝试验的残余浊度,Zeta电位和絮凝指数,研究了一价阴离子(Cl^-,ON₃^-)和二价阴离子(SO₄^2-)对聚二甲基二烯丙基铵盐(PDADMAX)的溶液性质、吸附的结构与形貌和絮凝性能的影响.结果表明:不同的反离子对PDADMAX的溶液性质、吸附的结构与形貌和絮凝性能有显著影响.PDADMANO₃具有更高的絮凝效率和“电中和作用”,而PDADMASO₄具有更宽的最佳絮凝范围和更大的絮体粒径,及更强的“吸附架桥作用”.特别对于聚电解质的吸附和絮凝机理的研究,单个高分子的原子力显微镜图象是一种非常有效地分析方法.

Atomic Force Microscope Analysis of Adsorption and Flocculation Behaviors of Polydiallyldimethylammonium Salts: Influence of Counterion

High molecular weight polydiallyldimethylammonium nitrate(PDADMANO₃) and polydiallyldimethylammonium sulfate(PDADMASO₄) were prepared from polydiallyldimethylammonium chloride(PDADMAC).The effects of univalent counterions(Cl^-,ON₃^-) and bivalent counterion(SO₄^2-) on solution,absorption and flocculation properties of polydiallyldimethylammonium salts(PDADMAX) were investigated by conductivity,reduced viscosity,atomic force microscopy(AFM),residual turbidity,distributions of zeta potential and flocculation index of kaolin suspension.The results show that different counterions possess significant effects on solution properties,absorption and flocculation behaviors of PDADMAX.PDADMANO₃ shows stronger flocculation efficiency and "neutralization action",whereas PDADMASO₄ shows the wider optimum dosage and larger floc size,as well as "bridging action".In particular,AFM image of single polyelectrolyte polymer is a valuable tool for the analysis of the absorption and flocculation mechanism of polyelectrolye.