4(%3)3 - Ecole nationale supérieure de chimie de Montpellier

freshly cut surfaces. The reason behind the all surface healing feature has been attributed to the abilityof the dynamers to constantly create new chain ends and form new connections.Figure – 1.26: Diels–Alder chemistry used to prepare, a) Reversibly cross-link fulvene functionalized glycol-basedpolymers with a cyanfumarate di-linker at room temperature, b) Room temperature healable film made from thecrosslinked polymer 151 .1.4.2.2 Sulfur ChemistrySulfur chemistry is another emerging strategy for inducing self-healing ability in a polymericsystem. The interesting feature which makes disulfide bonds important for this application is theircleavage under reducing conditions to give thiol groups which revert back to disulfide linkage in oxidizingconditions. Hence it is obvious from above feature that polymers consisting disulfide bridges can bereversibly crosslinked by effectively using reduction-oxidation conditions. Some notable workscapitalizing above this chemistry include the very first example of a reversibly crosslinkable polyoxazolinehydrogel with disulfide bonds 152 , ATRP derived polystyrene having disulfide bridge in the middle 153 , ATRPderived poly(ethylene glycol diacrylate) m -co-(poly(butyl acrylate)-b-poly(SS)) n star copolymers 154 (Figure –1.27).31