Seminars

The fracture resistance of soft materials is tightly coupled to the topology of polymer networks. Achieving control over this topology is therefore central to advancing the design of soft materials. In this talk, I will first review the importance of entanglement in the design of the elastic and fracture properties of polymer networks. Next, I will introduce two approaches that can engineer entanglements by mechanically and kinetically intervening in radical polymerization. Specifically, I will show that UV initiator concentration and light intensity influence network formation through distinct mechanistic routes, leading to measurable differences in elasticity and fracture properties. I will also discuss how applying mechanical stimuli via focused ultrasound during polymerization can control topology beyond thermodynamic equilibrium. These approaches are demonstrated using highly entangled hydrogels, which show significant differences in elastic and fracture properties due to the engineered polymer network topology. These techniques expand the accessible design space for polymer network topology and offer new routes for tuning mechanical response and fracture behavior in soft materials.