Commodity copolymers offer many useful applications, and their durability is critical in maintaining desired functions and retaining sustainability. These studies show that primarily alternating styrene/n-butyl acrylate [p(Sty/nBA)] copolymers self-heal without external intervention when monomer molar ratios are within the 45:55–53:47 range. This behavior is attributed to the favorable interchain interactions between aliphatic nBA side groups being sandwiched by aromatic rings forming ring-and-lock associations driven by pi–sigma–pi (π–σ–π) interactions. Guided by molecular dynamics (MD) simulations combined with spectroscopic and thermomechanical analysis, the ring-and-lock interchain van der Waals forces between π orbitals of aromatic rings and sigma components of aliphatic side groups are responsible for self-healing. Despite the frequent occurrence of these interactions in biological systems (proteins, nucleic acids, lipids, and polysaccharides), these largely unexplored weak and ubiquitous molecular forces between the soft acid aliphatic and soft base aromatic electrons may be valuable assets in the development of polymeric materials with sustainable properties.

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Safe and reliable fueling components are essential for large scale deployment of H2 fuel. Field data has shown that existing materials used in dispensing hoses do not meet current standards for component reliability. Currently modern copolymerization methods are under investigation to create a new platform for inner hose technologies using self-healable copolymers. Ideally these inexpensive self-healable copolymer inner layers will reduce the cost of H2 delivery hoses and extend their service life beyond 25,000 refills. In this work gas driven hydrogen permeability measurements were performed on a variety of self-healing copolymer membranes all of which have exhibited excellent self-healing properties in previous studies. Copolymers were prepared with Poly(2,2,2-trifluoroethyl methacrylate/n-butyl acrylate) [p(TFEMA/nBA)] and Poly(methyl methacrylate/nbutyl acrylate) [p(MMA/nBA)]. Measurements were performed through a range of temperatures and source pressures. Additionally, the effects of composition, copolymer ratio, and molecular weight on the hydrogen permeability, solubility, and diffusivity were all studied. As expected, hydrogen permeation through the samples is proportional to the source pressure and inversely proportional to the molecular weight of the polymer. In general, the self-healing copolymers exhibit hydrogen permeabilities consistent with literature data for similar elastomers. These results suggest this class of self-healable copolymers may be promising candidates for use as inexpensive inner layers in hydrogen dispensing hoses with extended service life.