posted on 2024-03-12, 22:18authored byCarlos
A. Salinas-Soto, Carlos Padilla-Gutierrez, Margarita Herrera-Alonso, Esteban E. Ureña-Benavides, Abelardo Ramírez-Hernández
Amphiphilic molecular bottlebrushes provide a rich platform
to
develop emulsifiers for highly responsive emulsions. An understanding
of the effect of the different molecular parameters on the structure,
organization, and interfacial properties of bottlebrushes at oil/water
interfaces is an important step toward the molecular engineering of
advanced bottlebrush surfactants. In this work, extensive numerical
simulations were performed to investigate the role of side chain and
backbone lengths, as well as polymer surface concentration, on polymer
structure, interfacial tension, and the organization of amphiphilic
mikto-grafted molecular brushes at planar oil/water interfaces. Simulation
results show that the side chain length is an important molecular
parameter: long side chains favor extended conformations at low surface
concentrations and higher local orientational order at high surface
concentrations. In addition, regarding thermodynamic interfacial properties,
simulation results predict that bottlebrushes with long side chains
and short backbones are better at reducing interfacial tension compared
to polymers with long backbones and short side chains, in agreement
with previous experimental observations. Several structural descriptors
were computed to provide a molecular view of the morphological changes
occurring as the polymer surface concentration and molecular parameters
were varied. The results reported here provide structure-interfacial
property relations that will be useful to have a deeper understanding
of how the molecular parameters of amphiphilic mikto-grafted molecular
brushes will affect their behavior at oil–water interfaces
to create advanced responsive emulsions.