运用原子力显微镜研究电解质溶液中白云母与二氧化硅间的相互作用力(英文)  

Interaction forces between muscovite and silica surfaces in electrolyte solutions measured with AFM

作　　者：蒋昊[1] 谢珍[1] 刘国蓉[1] 俞亚文[1] 张丁[1] 

机构地区：[1]中南大学资源加工与生物工程学院,长沙410083

出　　处：《中国有色金属学会会刊：英文版》2013年第6期1783-1788,共6页Transactions of Nonferrous Metals Society of China

基　　金：Project(50974134)supported by the National Natural Science Foundation of China;Project(2005CB623701)supported by the National Basic Research Program of China

摘　　要：运用原子力显微镜研究了二氧化硅胶体探针(直径,5μm)与白云母表面之间在电解质溶液环境下的相互作用力。试验考察了平衡时间、电解质浓度和溶液pH值对相互作用力的影响。实验结果表明,电解质浓度和溶液pH值对白云母/二氧化硅之间相互作用力及粘附力都产生显著的影响。在低电解质浓度和高的溶液pH值条件下,观察到一个很强的长程排斥力;而在高电解质浓度和低pH值条件下,两表面之间产生一个弱的长程吸引力。随着电解质浓度的增加,相互作用力从强的排斥力变化到强的吸引力。当溶液pH值在5.8～10.2时,相互作用是单调的排斥力;当溶液pH值降低至3.4时,在距离22～32nm处出现一个弱的吸引力。在低浓度或低pH值下,白云母与二氧化硅之间的粘附力比较大,随着电解质浓度和溶液pH值的增加,粘附力不断减小,最后相对稳定。运用经典DLVO理论对相互作用力进行理论计算,与实验曲线基本一致。Interaction forces between a silica colloidal sphere and a muscovite flat surface in electrolyte solutions were directly measured with an atomic force microscope (AFM). The results showed a significant impact of time, electrolyte concentration and solution pH on both long-range (non-contact) and adhesion (pull-off) force. A strong long-range repulsive force was observed under conditions of lower electrolyte concentration and higher solution pH, while a weak long-range attractive force was observed in the higher electrolyte concentration and lower pH solutions. With the electrolyte concentration increasing, the interaction forces decreased from strong repulsive force to strong attractive force. The measured long-range forces were monotonically repulsive at pH 5.8?10.2 and changed in a small scale. However, when the solution pH decreased to 3.4, a weak attractive force was observed at a separation distance of 22?32 nm. In low electrolyte concentration and pH solutions, the adhesion force between the muscovite and silica is large. With increasing the electrolyte concentration and solution pH, the adhesion force decreased and became relatively stable at last. The measured interaction forces were fitted well with the classical DLVO theory.

关 键 词：相互作用力 原子力显微镜 白云母 胶体探针 DLVO 

分 类 号：O647.1[理学—物理化学] P575[理学—化学]