Self-Healable Fluorinated Copolymers Governed by Dipolar Interactions

Abstract

Although dipolar forces between copolymer chains are relatively weak, they result in ubiquitous inter- and/or intramolecular interactions which are particularly critical in achieving the mechanical integrity of polymeric materials. In this study, a route is developed to obtain self-healable properties in thermoplastic copolymers that rely on noncovalent dipolar interactions present in essentially all macromolecules and particularly fluorine-containing copolymers. The combination of dipolar interactions between C─F and C═O bonds as well as CH2/CH3 entities facilitates self-healing without external intervention. The presence of dipole-dipole, dipole-induced dipole, and induced-dipole induced dipole interactions leads to a viscoelastic response that controls macroscopic autonomous multicycle self-healing of fluorinated copolymers under ambient conditions. Energetically favorable dipolar forces attributed to monomer sequence and monomer molar ratios induces desirable copolymer tacticities, enabling entropic energy recovery stored during mechanical damage. The use of dipolar forces instead of chemical or physical modifications not only eliminates additional alternations enabling multiple damage-repair cycles but also provides further opportunity for designing self-healable commodity thermoplastics. These materials may offer numerous applications, ranging from the use in electronics, ion batteries, H2 fuel dispense hoses to self-healable pet toys, packaging, paints and coatings, and many others.