We use a combination of computational and experimental techniques to study the self-assembly and gelation of water-soluble perylene bisimides derivatised at the imide position with an amino acid. Specifically, we study the likely structure of self-assembled aggregates of the alanine-functionalised perylene bisimide (PBI-A) and the thermodynamics of their formation using density functional theory and predict the UV-vis spectra of such aggregates using time-dependent density functional theory. We compare these predictions to experiments in which we study the evolution of the UV-Vis and NMR spectra and rheology of alkaline PBI-A solutions when gradually decreasing the pH. Based on the combined computational and experimental results, we show that PBI-A self-assembles at all pH values but that aggregates grow in size upon protonation. Gelation is driven not by aggregate growth but reduction of the aggregation surface-charge and a decrease in the colloidal stability of the aggregation with respect to agglomeration.
Updated discussion of thin film materials
PBI ala theory exp ESI ChemRxiv
PBI ala theory exp comp data
PBI ala theory exp exp data