Therefore, it is proposed that, whereas interactions between strong polyelectrolyte and polyelectrolyte brushes result in surface complexation and collapse, restricting molecular diffusion, RNA oligonucleotides induce weak collapse and enable infiltration, even within quaternised strong polyelectrolyte brushes such as PMETAI. This is analogous to the modest impact that DNA complexation was found to have on self-assembled monolayers of poly(styrene)-b-poly(4-vinyl methyl pyridinium) at air-liquid interfaces and resulting in slight complexation within the corresponding brush structure (it should be noted that such systems display modest grafting densities and are also associated with partial rearrangement of the soft poly(styrene) domains) .