Fluorophilic Sigma(σ)‐Lock Self‐Healable Copolymers

Abstract

Although F‐containing molecules and macromolecules are often used in molecular biology to increase the binding with Lewis acidic groups by introducing favorable C‐F dipoles, there is virtually no experimental evidence and limited understanding of the nature of these interactions, especially their role in synthetic polymeric materials. These studies elucidate the molecular origin of inter‐ and intra‐chain interactions responsible for self‐healing of F‐containing copolymers composed of pentafluorostyrene and n‐butyl acrylate units (p(PFS/nBA). Guided by dynamic surface oscillating force (SOF) and spectroscopic measurements supported by molecular dynamics (MD) simulations, these studies show that the reformation of σ‐σ orbitals in ‐C‐F of PFS and CH3CH2‐ of nBA units enables the recovery of entropic energy via flouorophilic‐σ‐lock van der Waals forces when PFS/nBA molar ratios are ~50/50. The strength of these interactions determined experimentally for self‐healable PFS/nBA compositions is in the order ~0.3 kcal/mol which primarily comes from flouorophilic‐σ‐lock (~70%) contributions. These interactions are significantly diminished for non‐self‐healable counterparts. Strongly polarized ‐C‐F σ orbitals create lateral dipolar forces enhancing the affinity towards ‐C‐H orbitals, facilitating energetically favorable interactions. Entropic recovery driven by non‐covalent bonding offers a valuable tool in designing materials with unique functionalities, particularly self‐healable batteries or other energy storage devices.