Patent ID: 8757395

Claim:
An article comprising: an expanded polytetrafluoroethylene (ePTFE) membrane having a Gurley versus bubble point equal to or below the line defined by the equation log(Gurley)=2.6×10 −3 (Bubble Point)−0.59, said ePTFE membrane having a surface area of at least 20 m 2 /g, wherein the bubble point of said ePTFE membrane is greater than or equal to the intersection of the line defined by the equation log(Gurley)=2.6×10 −3 (Bubble Point)−0.59 and the line defined by the equation log(Gurley) 5.13×10 −3 (Bubble Point))−1.58, and wherein the bubble point of said ePTFE membrane is less than or equal to about 877 kPa.