Bifunctional film

A bifunctional film, comprising:

• an anti-adhesion layer;
• and
• an attachment layer over the anti-adhesion layer,
• wherein the anti-adhesion layer comprises a first polymer mixture, and the first polymer mixture comprises:
• a first hydrophobic polymer which is at least one hydrophobic polymer selected from the group consisting of:
• polycaprolactone (PCL), polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA), poly(glycolic acid) (PGA), polyhydroxybutyrate (PHB), polydioxanone (PDS), poly(propylene fumarate) (PPF), polyanhydrides, polyacetals, poly(ortho esters), polycarbonates, polyurethanes, polyphosphazenes and polyphosphoester;
• and
• a first hydrophilic polymer which is at least one hydrophilic polymer selected from the group consisting of:
• hyaluronic acid (HA), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), polyethylene glycol (PEG), a derivative of polyethylene glycol and poly(ethylene oxide) (PEO), and
• in the anti-adhesion layer, a weight ratio of the first hydrophobic polymer to the first hydrophilic polymer is 1:0.01-1,
• wherein the anti-adhesion layer is formed by a step of drying a first polymer solution to form a film, and the first polymer solution comprises a first hydrophobic solution and a first hydrophilic solution, and the solute of the first hydrophobic solution is the first hydrophobic polymer, and the solute of the first hydrophilic solution is the first hydrophilic polymer,
• wherein the attachment layer consists of a second hydrophilic polymer, and the second hydrophilic polymer is at least one hydrophilic polymer selected from the group consisting of:
• gelatin, a modified gelatin, alginate, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), polyethylene glycol (PEG), a derivative of polyethylene glycol, collagen, demineralized bone matrix (DBM), bone morphogenetic protein (BMP), albumin, chitosan, fibrin, polyoxyethylene and polyvinylpyrrolidone, and
• wherein the attachment layer is formed by a step of drying a second polymer solution over the anti-adhesion layer to form a film, and the second polymer solution consists of a second hydrophilic solution, and the solute of the second hydrophilic solution is the second hydrophilic polymer.