Self-assembly of Polyhedral Oligomeric Silsesquioxane Structures Through Ion Exchange

In this study, we synthesized 3-chloroammoniumpropyl polyhedral oligomeric silsesquioxanes (CAP-POSS) by acid hydrolysis and condensation. Partial ion exchange resulted in the formation of supramolecular structures through electrostatic interactions. The interactions between POSS macroions were led by multiple hydrogen bonds that form supramolecular structures. After ion exchange, the structures of the CAP-POSS reduce the symmetry by the exchange of counterions and associate to form rigid transparent films at room temperature. The amount of chloride modulated the size and structure of macroions aggregates in the supramolecular films. Regardless of the amount of chloride removed, the films were formed of mass-fractal like structures with sizes ranging from 80 to 28 nm. The surface energy was proportional to the free amine content, and UV-vis was a light transmission characteristic. Therefore, the use of partial ion exchange represents an alternative to design of supramolecular POSS structures with properties tunable through multiple hydrogen bonds.