A new study by Henrique M. Cezar, Reidar Lund, and Michele Cascella from the Hylleraas Centre, in collaboration with researchers from Ca' Foscari University of Venice, has been published in Langmuir.
All authors: Henrique Musseli Cezar, Giacomo Berton, Tommaso Lorenzetto, Sandro Zorzi, Cedrix J. Dongmo Foumthuim, Szymon Mikołaj Szostak, Pablo Ballester, Claudia Mondelli, Ralf Schweins, Viviana Cristiglio, Fabrizio Fabris, Reidar Lund., Alessandro Scarso, Achille Giacometti, Michele Cascella.
6th February 2026; https://pubs.acs.org/doi/10.1021/acs.langmuir.5c05203
Findings
This work investigates an unconventional surfactant featuring a rigid hydrophobic triphenylene core and alternating hydrophobic and hydrophilic rim substituents. Using an integrative modeling approach that combines Small-Angle X-ray and Neutron Scattering (SAXS/SANS) with atomistic and coarse-grained molecular dynamics simulations, the study identified distinct aggregation patterns depending on the environment. In pure water, the molecules predominantly form small, well-defined stacks of up to six units, stabilized by π-stacking of the aromatic cores. The introduction of NaCl salt screens the repulsive electrostatic interactions between the charged sulfonate groups. This shielding facilitates further aggregation, leading to a morphological transition toward larger, elongated, and more disordered assemblies.
These findings highlight a salt-mediated mechanism that controls the size and shape of micelles in surfactants with complex, scrambled topologies. Overall, the study demonstrates how environmental factors such as local ionic strength can be utilized to manipulate matter at the molecular scale.
Abstract
Unconventional amphiphilic molecules having a rigid hydrophobic central unit and flexible or semiflexible hydrophilic chains on the rim have proven valuable in several technological applications, for example, host–guest chemistry. The further presence of alternating hydrophobic and hydrophilic tails complicates the definition of clear core and shell regions, resulting in complex segregation and frustrated self-assembly.
In this study, we investigate symmetric triphenylene-based amphiphilic derivatives with alternating benzyl and alkylsulfonate groups. We characterize their self-assembly in water and different solutions using several experimental techniques, including NMR, atomic force microscopy, dynamic light scattering, and small-angle X-ray and neutron scattering, alongside extensive molecular dynamics simulations, including both atomistic and coarse-grained integrative modeling with metainference. In aqueous solutions, these amphiphiles form stacked assemblies, adopting alternate up–down conformations driven by π-stacking of up to six molecules. The introduction of NaCl salt screens unfavorable electrostatic interactions, thus promoting further π-stacking and leading to the formation of larger elongated aggregates.