Date:
05-October-2026
Last Updated: 7
-October-2026
A commonly asked question is does a temperature change, even as little as a 1°C, significantly alter the inner Diameter of PEEK or PTFE Tubing?
INTRODUCTION
PEEK and PTFE tubing will expand and contract with temperature changes, but a 1°C temperature change results in an extremely small change in inner diameter (ID).
Theoretical Considerations
Both PEEK and PTFE expand when temperature increases. However, the amount of dimensional change associated with a 1°C temperature shift is generally very small. The thermal expansion coefficients of these materials indicate that even narrow tubing dimensions would change only by a few millionths of an inch per degree Celsius. For rigid tubing materials such as PEEK, these dimensional changes are often negligible compared to other factors that influence pressure-driven flow.
What Has a Greater Impact on Flow?
When evaluating flow rate changes in capillary systems, it is important to consider that fluid properties themselves are often more temperature-sensitive than the tubing dimensions. T emperature can affect:
- Solvent viscosity
- Solvent density
- Diffusion characteristics
- Backpressure within the system
In many cases, a flow change observed during a small temperature variation is more likely attributable to changes in solvent viscosity than to measurable expansion of the tubing bore.
Practical Experience
While thermal expansion is a real physical phenomenon, many chromatographers and fluidics users do not observe meaningful changes in tubing ID or system performance resulting from only a 1°C difference in ambient temperature. For applications using 0.007" ID tubing as a flow restrictor, a 1°C temperature fluctuation would not typically be expected to cause a dramatic change in resistance due solely to tubing expansion.
When Should Temperature Be a Concern?
Temperature control becomes increasingly important when:
- Working with highly viscous fluids
- Operating near critical flow tolerances
- Using long lengths of capillary tubing
- Conducting quantitative studies requiring exceptional reproducibility
In these situations, the influence of temperature on solvent properties often deserves more attention than thermal expansion of the tubing itself.
Conclusion
Although PEEK and PTFE tubing dimensions do change with temperature, the change associated with a 1°C temperature difference is expected to be very small. For most analytical and laboratory applications, temperature-induced changes in solvent viscosity are likely to have a much greater effect on flow behavior than changes in tubing inner diameter. When investigating temperature-related flow variations, it is often worthwhile to examine the fluid properties first before assuming a significant change in tubing dimensions.
Editor's Note: Have you observed measurable flow changes resulting from small temperature fluctuations in microfluidic, capillary, or chromatography systems? We'd be interested in hearing about your experience.