POS1-1668
Kinetic Interception of Crosslinker-First Ring-Opening Metathesis Polymerization Enables Architecture-Tunable Star Polymers
Topic
S1. Polymer Synthesis
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Hanjin Choi (Kyunghee University)
Co-Author(s)
Abstract
A recurring challenge in chemistry and materials synthesis is to use multifunctional building blocks to construct finite structures rather than extended networks. We herein show that incipient network formation in ring-opening metathesis polymerization (ROMP) can be kinetically intercepted and redirected into soluble, core-crosslinked star-shaped macromolecules. Bottom-Up ROMP Star (BURST) polymerization is a sequence-inverted, crosslinker-first strategy in which a bifunctional norbornene is polymerized before a monofunctional monomer. Rapid crosslinker consumption is followed by a pre-gelation interval during which compact nanogel cores continue to grow and retain metathesis activity. Timed addition of monofunctional norbornenes converts these transient intermediates into star polymers in one pot. The monomer feed and core growth time provide independently adjustable inputs that tune core/star dimensions and arm scaling behavior, affording compact stars with absolute molar masses up to 7.4 MDa. Hydrodynamic and scaling analyses reveal a core-size-dependent shift in arm organization, while microscopy resolves discrete star-derived particles. The architectural effects persist in the bulk, where stars exhibit enhanced glass-transition temperatures, strongly suppressed birefringence, and the ability to readily form intact free-standing films. BURST polymerization thus turns incipient gelation from an undesired outcome into a programmable intermediate that links reaction timing to molecular architecture and material properties.
