表面活性剂CTAB对二氧化硅表面间胶体作用力的影响

EFFECTS OF SURFACTANT CTAB ON INTERACTION BETWEEN SILICA SURFACES

在阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)溶液中,采用原子力显微镜原位检测二氧化硅表面间的胶体作用力变化。结果表明,CTAB的浓度、电解质及稳定时间均会影响二氧化硅表面间的长程作用力和黏着力及二氧化硅表面的润湿性。在不含电解质KCl的溶液中,随着CTAB浓度的增加,CTAB在二氧化硅表面的吸附量不断增加,二氧化硅表面间的长程作用力由吸引力转变为排斥力。当CTAB溶液中含有浓度为10 mmol/L的KCl时,随着CTAB的浓度增加和稳定时间的延长,二氧化硅表面间的长程作用力增加,二氧化硅表面润滑性增强,当CTAB浓度增大到1.00 mmol/L和10.00 mmol/L时,长程作用力为排斥力,二氧化硅表面为水润性。电解质和稳定时间对二氧化硅表面间胶体作用力的影响能反映CTAB在二氧化硅表面吸附形态的变化,从而反映二氧化硅表面的电性能和润湿性。

In the cationic surfactant hexadecyl trimethylammonium bromide(CTAB)solution,the changes of interactions between the silica surfaces were detected by atomic force microscopy in situ.The results showed that there were significant impacts of concentration of CTAB,electrolytes and incubation time on both the long-range interactions and adhesion forces between silica surfaces,and the wettability of the sand surfaces.In the solution without electrolyte KCl,with the increase of CTAB concentration,the adsorption amount of CTAB on the surface of silicon dioxide increases continuously,and the long-range force between the surfaces of silicon dioxide changes from attractive force to repulsive force.It was further observed that addition of KCl(10 mmol L)in CTAB solutions would enhance the colloidal interactions with the concentration of CTAB and incubation time.At 1.00 mmol L and 10.00 mmol L of concentration of CTAB,the long-range force became repulsive.The effect of electrolyte and stabilization time on the colloidal forces between SiO 2 surfaces can reflect the changes of adsorption morphology of CTAB on SiO 2 surfaces,thus reflecting the electrical properties and wettability of SiO 2 surfaces.