Filter media having a fine pore size distribution

A filter media comprising:

• a first fiber web comprising first fibers having an average diameter of less than or equal to 0.5 microns, wherein the first fibers comprise electrospun fibers and wherein the first fiber web has a thickness of less than or equal to 200 microns;
• a calendered fiber web directly adjacent to the first fiber web;
• and
• a third fiber web bonded to the first fiber web;
• wherein the filter media has a maximum pore size of greater than or equal to 0.1 microns and less than or equal to 2.5 microns, a full width at half maximum of a pore size distribution of less than or equal to 0.2 microns, and a ratio of maximum pore size to mean pore size of less than or equal to 5.0.

A filter media comprising:

• a first fiber web comprising first fibers, wherein the first fibers comprise electrospun fibers and have an average diameter of less than or equal to 0.5 microns, wherein the first fiber web has a thickness of less than or equal to 200 microns;
• a second fiber web directly adjacent to the first fiber web, wherein the second fiber web has a dry tensile strength in the machine direction of greater than or equal to 1 lb/in and less than or equal to 35 lb/in, a dry tensile elongation in the machine direction of greater than or equal to 10% and less than or equal to 60%, and a mean pore size of greater than or equal to 1 micron and less than or equal to 30 microns;
• and
• a third fiber web bonded to the first fiber web;
• wherein the filter media has a maximum pore size of greater than or equal to 0.1 microns and less than or equal to 2.5 microns, and a full width at half maximum of a pore size distribution of less than or equal to 0.2 microns.

A filter media comprising:

• a first fiber web comprising first fibers, wherein the first fibers comprise electrospun fibers and have an average diameter of less than or equal to 0.5 microns, wherein the first fiber web has a thickness of less than or equal to 200 microns;
• a second fiber web directly adjacent to the first fiber web, wherein the second fiber web has a surface mean pore area of greater than or equal to 2 μm2 and less than or equal to 50 μm2, an intersection density of greater than or equal to 0.005 intersections/μm2 and less than or equal to 0.025 intersections/μm2, and a mean pore size of greater than or equal to 1 micron and less than or equal to 30 microns;
• and
• a third fiber web bonded to the first fiber web;
• wherein the filter media has a maximum pore size of greater than or equal to 0.1 microns and less than or equal to 2.5 microns, and a full width at half maximum of a pore size distribution of less than or equal to 0.2 microns.