Mechanical Stability of Porous Multilayer Polymer Films—Separators in Lithium-Ion Batteries

Abstract: We have used known theoretical approaches, namely, Grosberg–Khokhlov and Flory theory, for description mechanical properties of porous polymer films in electrolyte solvents. In both approaches, in good solvents, with the increase in the swelling ratio α, the Young’s modulus asymptomatically decreases to zero, i.e. films are softened. In Grosberg–Khokhlov’s theory, it has been shown that the Young’s modulus is maximal at the swelling ratio α = 1 that corresponds to the dry film or the film in θ-solvent. In this theory, the effect of hardening of porous films (the poroelastic effect) is impossible in any good solvents, and the film is always softened. However, in Flory theory, such solvent may be always selected where the poroelastic effect may be realized. © 2023, Allerton Press, Inc.