Fluorophilic Sigma(σ)-Lock Self-Healable Copolymers.

Area of Science:

• Polymer Science
• Materials Science
• Organic Chemistry

Background:

• Fluorine-containing molecules enhance binding via C-F dipoles, but their interactions in polymers are poorly understood.
• Understanding these interactions is crucial for developing advanced synthetic polymeric materials.

Purpose of the Study:

• To elucidate the molecular origin of inter- and intra-chain interactions in self-healing fluorinated copolymers.
• To investigate the role of fluorophilic-σ-lock van der Waals forces in polymer self-healing.

Main Methods:

• Dynamic surface oscillating force (SOF) and spectroscopic measurements.
• Molecular dynamics (MD) simulations.
• Experimental determination of interaction strengths in self-healable and non-self-healable compositions.

Main Results:

• Self-healing in pentafluorostyrene/n-butyl acrylate copolymers (p(PFS/nBA)) at ~50/50 molar ratios is driven by the reformation of σ-σ orbitals via fluorophilic-σ-lock forces.
• These interactions contribute ~0.3 kcal/mol, with ~70% from fluorophilic-σ-lock, and are diminished in non-self-healable materials.
• Polarized C-F σ orbitals create dipolar forces enhancing affinity towards C-H orbitals, facilitating energetically favorable interactions.

Conclusions:

• Entropic recovery driven by non-covalent bonding, specifically fluorophilic-σ-lock forces, is key to self-healing in these polymers.
• This understanding provides a pathway for designing materials with enhanced functionalities.
• Potential applications include self-healable batteries and energy storage devices.