Conférence de Chimie
Par le Professeur Christopher Bowman
TITRE:
Smart, Responsive Polymers Based on Covalent Adaptable Networks:
Photoactivatable Dynamic Covalent Chemistry and Its Applications in Polymer Networks
Lien ZOOM:
https://umontreal.zoom.us/j/95221383560?pwd=MURCTHVXSHZPZDNZKzh1SnFTVWV5dz09
ID de réunion : 952 2138 3560
Code secret : 170221
RÉSUMÉ:
Polymer networks possessing dynamic covalent crosslinks constitute a class of materials with unique capabilities including the capacity for adapting to an externally applied stimulus. These covalent adaptable networks (CANs) represent a paradigm in polymer network fabrication aimed at the rational design of structural materials possessing dynamic characteristics for specialty applications and functions. Here, we explore several distinct approaches to CANs based on photochemically triggered responses. First, those in which the reversible bond formation, based on addition-fragmentation, occurs only during exposure to light will be discussed, enabling polymer network relaxation, photoinduced actuation and shape memory effects, and stress relaxation. Using liquid crystalline elastomer networks of this type, we will demonstrate the solution to fitting a square peg into a round hole, reversibly. Secondly, using thiol-thioester exchange chemistry, we will discuss the formation of a material that is capable of undergoing a bistable transition from a viscoelastic solid to a viscoelastic fluid, induced by light. Using this approach, we demonstrate recyclability, healing, and enhanced toughness of materials based on these types of networks. Ultimately, the potential for CANs-based materials to impact numerous materials applications will be presented in light of their distinctive array of material properties.
