Polyethylene-based porous oil sorbent with swellable pockets

A method for preparing a freestanding porous polyethylene thin film, the method comprising:

• dissolving polyethylene in an organic solvent to form a solution under reflux conditions;
• adding a swellable pocket forming agent to the solution and mixing the solution until the swellable pocket forming agent is well-dispersed therein, thereby forming a well-dispersed solution;
• placing a solid substrate onto a spin coater chuck;
• applying the well-dispersed solution onto the solid substrate through spin coating to form a thin film on the solid substrate;
• collecting excess materials of the polyethylene and the organic solvent in a spin coated drain connected to a receiver;
• removing the solid substrate with the thin film formed thereon from the spin coater chuck;
• subjecting the formed thin film to post-heat;
• peeling the thin film off the solid substrate to obtain a peeled thin film;
• and
• extracting the swellable pocket forming agent from the peeled thin film by washing the peeled thin film in water, thereby obtaining a freestanding porous polyethylene thin film with swellable pockets, macro-voids, and micropores, wherein each of the swellable pockets are configured to swell twenty to thirty times a thickness of the freestanding porous polyethylene thin film when in contact with oil.