Effects of mechanical softening and hardening of porous polymer films in solvents

The Grosberg–Khokhlov theory was used to describe the mechanical properties of porous polymer films in good solvents. It is shown, as in the well-known Flory's theory of polymer solutions, the swelling of films and the involvement of solvent in them makes it possible to detect effects of mechanical softening and hardening of films. In both theories, similar dependences of the Poisson's ratio on the Flory–Huggins interaction parameter are obtained, These dependences make it possible to select an ideal $(\theta)$ solvent in which the Young's modulus of the film is the same or greater than for a dry film.