Study of the effect of different surfactants on the stability of titanium dioxide dispersions based on optical tweezers

Switchable surfactants are key to the stability of titanium dioxide dispersions. In this study, we used dual trap optical tweezers to measure the inter-particle force dynamics of titanium dioxide particles in dispersions with different surfactants. The results of the inter-particle force interactions were fitted using the DLVO theoretical model. The experimental results show that the interaction force on the surface of bare titanium dioxide particles was almost zero, which was consistent with the theoretical results, while the inter-particle interaction force changed significantly in the presence of different surfactants. The effects of different surfactants on the stability of their dispersions were also different: SHMP⪆SDBS⪆CTAB⪆F68⪆SDS⪆OP-10. In addition, the effects of mixed surfactants and salt solutions on the stability of titanium dioxide dispersions were also compared, and the results showed that the mixing ratios had similar stabilizing effects.