PVDF and PTFE share a fluorine atom in their chemistry class photo, but that's where the family resemblance ends. They solve completely different engineering problems, and swapping one for the other usually ends badly.
We stock and machine both. Here's how they actually compare in practice — not on datasheets, but in the machine and in the field.
The chemistry, in plain terms
PTFE is a chain of carbon atoms completely surrounded by fluorine. The fluorine sheath is dense and inert — nothing sticks to it, nothing dissolves it, and the chains slide past each other with almost no friction. That's also why PTFE creeps under load: those chains have nothing holding them together except weak van der Waals forces.
PVDF alternates fluorine and hydrogen atoms along the carbon backbone. The hydrogen atoms create polarity — the chains attract each other more than PTFE's do. Result: PVDF is mechanically stronger and stiffer, can be melt-processed (injection molded, welded), but gives up some of PTFE's extreme chemical and thermal resistance.
Temperature: the dealbreaker
PTFE works continuously at 260°C. PVDF tops out at 150°C. That 110°C gap is the single biggest differentiator.
If your application runs hot, you're choosing PTFE. If it runs under 150°C, PVDF's mechanical advantages become relevant.
Chemical resistance
PTFE is functionally immune to everything except molten alkali metals and elemental fluorine at high pressure. It's the gold standard for chemical compatibility.
PVDF is very good — better than most engineering plastics — but not PTFE-level. Strong bases, fuming acids, and some ketones attack it. For semiconductor wet process at moderate temperatures, PVDF handles most chemistries. For the harshest environments (hot concentrated acids, chlorine gas, etc.), PTFE is the answer.
Mechanical: PVDF is actually stronger
This surprises people. PVDF has roughly double the tensile strength of PTFE (50 MPa vs 25 MPa) and a modulus about 3x higher. PTFE is mechanically quite weak — it deforms under sustained load at room temperature.
For a structural part, PVDF carries more load at a given cross-section. For a gasket or seal where conformability matters more than strength, PTFE's softness is an advantage.
Friction and wear
PTFE has the lowest coefficient of friction of any solid — about 0.05-0.10 against steel, unlubricated. It's the benchmark for low friction.
PVDF's friction is higher (0.15-0.30). Neither wears particularly well in pure form; filled grades (carbon, graphite, glass) improve wear resistance in both. But for pure low-friction applications, PTFE wins.
Machinability
PTFE is a machining challenge — it's so soft that it deforms under cutting pressure, springs back after the tool passes, and creeps dimensionally. Sharp tools, light cuts, stress-relieved stock. Even then, ±0.05mm is a realistic limit.
PVDF machines more like a conventional plastic. It holds tolerance better, burrs less, and doesn't creep nearly as much. You can hold ±0.025mm in PVDF with proper process control.
Electrical
Both are excellent insulators. PTFE's dielectric constant is slightly lower (2.0 vs 6-8 for PVDF), and it maintains electrical properties better at high frequencies, which is why PTFE dominates in RF and microwave substrates.
A practical comparison
| What matters | Pick PTFE when | Pick PVDF when |
|---|---|---|
| Temperature | Above 150°C | Below 150°C |
| Chemical exposure | Worst-case (strong acids, solvents) | Moderate (most industrial) |
| Mechanical load | Low (seal, gasket, liner) | Higher (structural, pressure) |
| Tolerance | ±0.05mm is OK | Need ±0.025mm or better |
| Friction | Lowest possible | Low-to-moderate is fine |
| Weldability | Can't be welded | Weldable (pipe, tank lining) |
| Cost | Higher | Moderate |
Our take
For semiconductor wet benches at moderate temperature, PVDF is the default choice because you can weld it into complex shapes and it handles most process chemistries fine. For high-temperature etch or aggressive chemical environments, PTFE is non-negotiable.
For gaskets and seals, PTFE still rules. For structural chemical-processing components under 150°C, PVDF often makes more sense than engineers realize.
If you're stuck between the two, send us the operating conditions (temperature range, chemicals, mechanical load, tolerance requirements). We'll tell you which one makes sense and why.