Preparation and enhanced oil recovery study of amphiphilic Janus nanosheets

This study introduced an innovative approach for the synthesis of amphiphilic Janus nanosheets. Thermally expandable microspheres (TEMS) were used as a template, and tetraethyl orthosilicate (TEOS) was used as a silicon source. Janus spheres with TEMS as the core and SiO 2 as the shell (TEMS@SiO 2 ) were synthesized under alkaline conditions. Janus spheres (TEMS@SiO 2 -NH 2 ) were further modified by aminopropyltriethoxysilane (APTES). Janus nanosheets (SiO 2 -NH 2 ) were obtained by heating to expand the TEMS. Amphiphilic Janus nanosheets C 16 -SiO 2 -NH 2 (CSAJN) were prepared by modifying Janus nanosheets (SiO 2 -NH 2 ) with hexadecyltrimethoxysilane (HDTMS). CSAJN was characterized by fourier transform infrared spectroscopy (FT-IR) , thermogravimetry (TG) , a laser particle size analyzer , scanning electron microscopy (SEM) , (tetraethyl orthosilicate) TEM , and a contact angle goniometer. The results indicated that CSAJN had a lamellar structure with a thickness of 41 nm and a size of 260 nm. The interfacial tension of CSAJN nanofluid (1000 mg/L) at the oil -water interface was 1.4 mN/m at 60 degrees C. CSAJN nanofluid (1000 mg/L) exhibited excellent emulsification ability at 60 degrees C, with an emulsification index of 0.68 over 240 h. CSAJN nanofluid (1000 mg/L) could maintain stability after 10 days. CSAJN nanofluid (1000 mg/L) demonstrated outstanding wetting properties, transforming from oil-wet to water-wet on core slices (103 degrees to 39.4 degrees ). Compared to water flooding, CSAJN nanofluid (1000 mg/L) significantly enhanced oil recovery.