PFSA
Nafion (Perfluorosulfonic Acid)
Glass Transition (Tg)
~110 °C
Melting Point (Tm)
—
Density
1.98 g/cm³
CAS Number
31175-20-9
Recycling Code
♺ 7
Category
Functional & Smart
Repeat Unit
–[CF₂–CF₂]ₓ–[CF₂–CF(O–C₃F₆–O–C₂F₄–SO₃H)]ᵧ–
The repeating unit is the smallest structural fragment whose repetition builds the whole chain. Subscripts show the relative share of each unit in copolymers.
Key Properties
Phase-separated ionomer: hydrophobic PTFE backbone with hydrophilic sulfonic clusters forming water channels for proton conduction.
Applications
PEM fuel-cell membranes, chlor-alkali cells, electrolysers.