Filter media ribbons with nanofibers formed thereon

A method for making polymeric objects having a surface on which is formed an array of nanofibers, the method comprising:

• providing a rotating mold with an array of nanoholes formed in a circumferential surface thereof;
• applying a flowable polymer to the rotating mold at a first angular location so that the flowable polymer coats at least a portion of the circumferential surface of the rotating mold and infiltrates at least a portion of the nanoholes;
• cooling the flowable polymer while the coated rotating mold rotates to a second angular position;
• and
• removing the cooled polymer from the rotating mold as an elongate film;
• wherein the polymer that infiltrated the nanoholes forms the array of nanofibers on a surface of the elongate film.

A method for making polymeric objects having a surface on which is formed an array of nanofibers, the method comprising:

• providing a mold with an array of nanoholes formed in a surface thereof;
• applying a malleable polymer to the mold so that the malleable polymer covers at least a portion of the surface of the mold and infiltrates at least a portion of the nanoholes;
• compressing the malleable polymer against the surface of the mold with a compressing element maintained at a temperature that causes the malleable polymer to solidify in the nanoholes along with a portion of the polymer covering the surface of the mold;
• removing the solidified polymer from the mold as a film;
• wherein the polymer that infiltrated the nanoholes forms the array of nanofibers on a surface of the film.