How should I prepare electrospun fibers for BET analysis? How much (cm x cm) should I cut to obtain reliable results? What about degassing? I have PLA sample, 40 C will be enough?
Generally, a sample of 0.5-1 g or 2x 2 cm2 is sufficient for BET analysis. However, the required sample size may vary depending on the properties of the sample. The recommended degassing temperature is typically around 100°C for approximately 3 hours, which is likely to be suitable.
If your fibers are of smooth nature and more towards micro-size you should prepare bigger sample (by weight). Usually 1g is sufficient for fibers 500 nm-1 um but as you will probably realise putting 1g of electrospun membrane in the BET measurement vial is not that simple. My suggestion is to prepare up to 1 g of material and discuss with your BET technician what is maximum amount of material you can stack in BET vial without influencing negatively the measurement.