Surfactants used in nanofluids are known as dispersants. Adding dispersants to two-phase systems improves the stability of nanofluids in a simple and cost-effective approach. Even little concentrations of dispersants can have a big influence on a system's surface characteristics. A hydrophobic tail component, usually a long-chain hydrocarbon, plus a hydrophilic polar group make up dispersants. Dispersants are used to improve the wettability of two materials by increasing the contact between them. In a two-phase system, a dispersion is frequently observed around the interface of two phases, where it introduces a degree of continuity between the nanoparticles and the base fluids. On-ionic surfactants (polyethylene oxide, alcohols, and other polar groups), anionic surfactants with negatively charged head groups (anionic head groups include long-chain fatty acids, sulfosuccinates, alkyl sulphates, phosphates, and sulfonates), and cationic surfactants with positively charged head groups (cationic surfactants may be protonated) are the four types of surfactants classified by their head composition (charge depends on pH.)