  Antiagglomerants (AAs) are surface active molecules widely used in the rubber
and petroleum industry, among others. In the petroleum industry, it is believed
that AAs strongly adsorb to the surface of hydrate particles to prevent the
growth of clathrate hydrate within oil pipelines. Small changes in their
molecular structures can strongly affect the thermodynamic and kinetic
stability of the system as a whole. Here we employ molecular dynamics
simulations to study the interplay between the modification of the molecular
structure, rigidity and collective effects of AAs designed to prevent hydrate
agglomeration in the conditions encountered in rocking cell experiments. The
AAs are surface-active compounds with a complex hydrophilic head and three
hydrophobic tails whose structural rigidity is enhanced with the attachement of
a simple aromatic group. We observe that the aromatic group can positively or
negatively affect the performance of the AAs, depending on its location along
the hydrophobic tail. Our approach is based on first quantifying the molecular
mechanisms responsible for the macroscopic performance. Although the mechanisms
at play depend on the application, the methodology implemented could be
applicable to other high-tech industries, where the agglomeration of small
particles must be controlled.
