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

As the human civilization progress more and more each day, our demands for energy and materialare growing at an exponential rate. Polymers and their composites hold an important andsignificant share in type of materials that drive the current global technology scenario. Millions of tonnesof different kinds of polymer are produced each year to meet the ever increasing need. At same time ithas given rise to the problem of piling up of huge polymeric waste and degraded materials. On the otherhand, if we look closely to nature, we can easily see that it produces complex chemicals and materials insuch an efficient and clean manner that there are no wastages or after effects. It recycles the broken ordamaged parts in an exquisite fashion by virtue of regeneration process. This regeneration process, i.e.the “Self-Healing” capability is one of the several interesting ideas from nature that humans have tried toreplicate in their quest for novel technology.The concept of Self-Healing materials can be considered as a resurrected one, which remaineddormant for significant number of years even though being first discussed in the 50s and 60s. Thedomain of self-healing polymers has seen a tremendous advancement in last two 15 years, thanks topioneering work of researchers at Illinois university, who developed the microcapsule based self-healingcomposites. The concept opened the door for new direction to develop such kinds of materials whichcould heal themselves in a more simplistic manner than the ones in nature. The success of this approachmade others to develop their own strategies to impart self-healing property to polymeric materials.Some of these approaches involving dynamic covalent or non-covalent bonding led to the developmentof novel series of polymers and composites. As more and more advances are made in chemistry, therestill exist a whole lot of possibilities to develop even better and more efficient self-healing polymericsystems.The main aim of this thesis is to bring the self-healing concept within the domain of polymericmembranes and develop such kind of membranes which can repair themselves in an event of damage.Unlike their solid state counterparts, membranes being a porous material pose some challenges of theirown kind when applying the same kind of self-healing techniques. One of the main objective andchallenge is to develop a complete autonomous self-healing mechanism for a polymeric membranewithout affecting its principal property of separation.The first chapter of this manuscript provides an outlook towards the idea of self-healing rightfrom its beginning till the current scenario. We begin by discussing about the characteristics of failurethat occur in a polymer during the course of its lifetime. This is followed by the classification of the selfhealingapproaches developed so far, although there are also other possible ways to classify thesematerials. We have broadly classified the self-healing polymeric systems in autonomous and nonautonomousones, which are further sub-classified. The chapter provides only those works that have