Photomediated Cationic Ring-Opening Polymerization of Cyclosiloxanes with Temporal Control

Precision synthesis of polyorganosiloxanes and temporal control over the polymerization process during ring-opening polymerization (ROP) of cyclosiloxanes remain challenging due to the occurrence of side reactions, e.g., intramolecular transfer (backbiting) and intermolecular chain transfer, and irreversible catalyst transformation. In this study, a merocyanine-based photoacid catalyst is developed for cationic ROP of different cyclosiloxanes. A series of well-defined cyclotrisiloxane polymers with predetermined molar masses and low dispersities (