Polymer electrolyte membrane

A polymer electrolyte membrane comprising:

• a porous film;
• and
• a polymer electrolyte,
• the porous film having a fibril/node area ratio of 90/10 to 75/25 and a contact angle with a solution of the polymer electrolyte of 44 degrees or smaller,
• wherein the porous film having a film density of 0.80 g/cm3 or lower,
• wherein the polymer electrolyte is a fluoropolymer electrolyte, wherein the fluoropolymer electrolyte is a copolymer comprising
• a repeating unit derived from a COOZ or SO3Z group-containing monomer represented by the following formula (I):
• CF2=CF(CF2)k—O1—(CFY2)m-A1 (I)
• wherein k is an integer of 0 to 2;
• 1 is 0 or 1;
• m is an integer of 0 to 12, if m=0, then 1=0, when m is an integer of 1 to 12, Y2 is F or Cl and m Y2s may be the same as or different from each other;
• A1 is COOZ or SO3Z, where Z is an alkali metal, an alkaline earth metal, hydrogen, or NR1R2R3R4, where R1, R2, R3, and R4 are each individually a C1-C3 alkyl group or hydrogen, and
• a repeating unit derived from tetrafluoroethylene.