Interfacial Effects of Nonionic and Anionic Surfactants on the Colloidal Stability of Graphene and Al ₂ O ₃ Nanoparticles in Jet-A/Sustainable Aviation Fuel Blends

High Resolution Image Download MS PowerPoint Slide Sustainable aviation fuel (SAF), such as hydrotreated vegetable oil (HVO) mixed with Jet-A, has attracted increasing interest as an alternative aviation fuel to reduce aircraft-related emissions and support long-term decarbonization targets. The incorporation of nanoparticles has been reported to enhance the physicochemical and thermophysical performance of the blends. However, the practical implementation of nanoparticle-based SAF blends is constrained by challenges associated with the long-term colloidal stability in nonpolar fuel systems. In this study, the interfacial effects of nonionic and anionic surfactants on the colloidal stability of graphene (Gr) and aluminum oxide (Al 2 O 3 ) nanoparticles dispersed in Jet-A/HVO blends were systematically investigated. Cetyltrimethylammonium bromide (CTAB), sorbitan monooleate (SPAN 80), and sodium dodecylbenzenesulfonate (SDBS) were evaluated at surfactant-to-nanoparticle ratios of 1:0.5, 1:1, and 1:2 to identify optimal stabilization conditions. Nanofuels were prepared using a two-step dispersion approach comprising magnetic stirring followed by ultrasonic homogenization to minimize nanoparticle agglomeration. The morphologies of Gr and Al 2 O 3 were characterized using scanning electron microscopy. Colloidal stability was assessed through visual sedimentation observations, thermal conductivity measurements, and ζ-potential analysis. The results indicate that SPAN 80 provides superior interfacial compatibility with both nanoparticles in the fuel blends compared to CTAB and SDBS, resulting in enhanced dispersion stability. Optimal stabilization was achieved at a surfactant-to-nanoparticle ratio of 1:1 for Gr and 1:2 for Al 2 O 3, as achieved by higher absolute ζ-potential values and improved thermophysical behavior. These findings demonstrate the critical role of surfactant chemistry and interfacial interactions in governing the colloidal stability of nanoparticle-containing sustainable aviation fuel blends.