School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, PR China.
Langmuir. 2010 Aug 3;26(15):12567-74. doi: 10.1021/la1016559.
The in situ surface activation of unmodified CaCO(3) nanoparticles by interaction with surfactant in aqueous media has been studied, and the impact of this on the foamability and foam stability of aqueous dispersions was assessed. Using complementary experiments including measurement of particle zeta potentials, adsorption isotherms of surfactant, air-water surface tensions, and relevant contact angles, the mechanism of this activation was revealed. The results show that the non-surface-active CaCO(3) nanoparticles cannot be surface activated by interaction with cationic or nonionic surfactants but can be surface activated by interaction with anionic surfactants such as SDS and AOT, leading to a synergistic effect in both foamability and foam stability. The electrostatic interaction between the positive charges on particle surfaces and the negative charges of anionic surfactant headgroups results in monolayer adsorption of the surfactant at the particle-water interface and transforms the particles from hydrophilic to partially hydrophobic such that particles become surface active and stabilize bubbles. SDS is a more efficient surfactant for this surface activation than AOT. Possible reasons for this difference are suggested.
已经研究了通过与水介质中的表面活性剂相互作用原位表面激活未改性 CaCO(3)纳米粒子，并且评估了这种作用对水基分散体的起泡性和泡沫稳定性的影响。使用包括测量颗粒zeta 电位、表面活性剂吸附等温线、气-水表面张力和相关接触角的补充实验，揭示了这种活化的机制。结果表明，非表面活性的 CaCO(3)纳米粒子不能通过与阳离子或非离子表面活性剂的相互作用而被表面激活，但可以通过与阴离子表面活性剂（如 SDS 和 AOT）的相互作用而被表面激活，从而在起泡性和泡沫稳定性方面产生协同效应。颗粒表面上的正电荷与阴离子表面活性剂头基的负电荷之间的静电相互作用导致表面活性剂在颗粒-水界面上单层吸附，并将颗粒从亲水转变为部分疏水，从而使颗粒具有表面活性并稳定气泡。SDS 比 AOT 更有效地用于这种表面激活。对于这种差异，提出了可能的原因。
