Surfactants are essential to modern life, yet their performance is still largely optimised empirically, with limited molecular-level understanding of how structure governs function. Here, we present a systematic investigation of heteroaromatic surfactants, focusing on how heteroaromatic headgroup motifs modulate amphiphilic behaviour and interfacial performance. Building on bio-derived systems such as sulfonated alkyl furoates, we test the hypothesis that heteroaromaticity alters effective hydrophobicity, thereby influencing micellisation, adsorption, and macroscopic properties.
A series of heteroaromatic surfactants, including furan-, thiophene-, and pyrrole-based alkyl sulfonates, was synthesised and systematically characterised. Key physicochemical properties, including critical micelle concentration and surface excess, were evaluated alongside application-relevant metrics such as foaming performance and Zein protein solubilisation. Across the series, clear differences in interfacial behaviour were observed, indicating that heteroaromatic structure modulates hydration, packing, and effective hydrophobicity.
To rationalise these observations, molecular dynamics simulations were employed to predict interfacial tensions and the Gibbs free energy of transfer from water to oil as a quantitative descriptor of hydrophobicity. The simulation results show strong agreement with experimental trends, demonstrating that heteroaromatic motifs systematically tune surfactant behaviour by altering hydration thermodynamics and interfacial adsorption. Together, these findings establish a direct link between molecular structure, hydrophobicity, and macroscopic performance in heteroaromatic surfactant systems.
These findings provide new insights into how molecular features influence amphiphilic self-assembly and interfacial phenomena, offering a predictive basis for surfactant design. More broadly, this work contributes to the fundamental understanding of structure–property relationships in amphiphilic systems and supports the development of next-generation surfactants with improved efficiency, mildness, and sustainability.
