US Patent 11904581 Bifunctional film

A method for preparing a bifunctional film, including: (a) drying a first polymer solution to form a film to form an anti-adhesion layer, and (b) drying a second polymer solution over the anti-adhesion layer to form a film to form an attachment layer. The first polymer solution includes a first hydrophobic solution and a first hydrophilic solution, and in the first polymer solution, the weight ratio of the solute of the first hydrophobic solution to the solute of the first hydrophilic solution is 1:0.01-1. Moreover, the second polymer solution is composed of a second hydrophilic solution.