The study of novel amphiphilic Janus-SiO₂ nanoparticles for enhanced viscoelasticity of wormlike micelles

Wormlike micelles (WLMs) with superior viscoelasticity exhibited great potential application in petroleum industry. Compared with polymer systems, the relatively low viscoelasticity of WLMs should be fur-ther improved effectively. In this study, the amphiphilic Janus-SiO2 nanoparticles (JAnC NPs, n represents the carbon atoms number of modified alkyl chain) were successfully fabricated, which were verified by Fourier transform infrared spectra and water contact angle measurements. Then the effects of additional JA3C NPs on the viscoelasticity of WLMs solutions formed by stearyltrimethylammonium bromide/ -sodium salicylate were systemically explored via rheology behavior and cryo-TEM pictures. Compared with original isotropic SiO2 NPs, the amphiphilic JAnC NPs showed greater ability to improve the WLMs viscoelasticity. To explore the enhanced mechanism, the zeta potential of STAB/SiO2 dispersions and the viscosity of WLMs formed by various surfactants with additional JAnC NPs were studied in the controlled experiments. In addition, a mathematical model was employed to calculate the quantity of junctions between micelles and NPs in different WLMs/NPs systems to confirm the proposed mechanism. This work firstly investigated the effects of the novel Janus-SiO2 NPs on the WLMs viscoelasticity.(c) 2022 Elsevier B.V. All rights reserved.