Hi. I did intercalation using NMP and crystal is attatched to the substrate using mechanical exfoliation. I did annealing after exfoliation so that crystal is attached to the substrate well. But after all experiment was done, some residue from NMP remained on the surface of substrate. I would like to clean it out but i don't know how i can remove only NMP while keeping the crystal untouched. Is there anyone who knows?
NMP can be removed during vacuum treatment of sample, maybe using weak heating (I used in different cases 40-100 C). You need to determine the "safe" temperature for the sample. It is also necessary to find a method for determining concentration of residual NMP in a sample.
Water treatment is very undesirable since water is a very polar solvent.
Dear Seorin Cho ,
NMP is water-soluble so you should wash multiple times in the water . or you can follow the below discussion as Rob Darrington suggested
Removal of NMP can be challenging, and generally does require the correct apparatus. We would generally not advise using a basic freeze dryer as plastic / elastomer components and the vacuum pump may all suffer damange by NMP. NMP boils at 202°C and melts at -24°C. My guess is that with vacuum alone you will not get the pressure low enough to keep NMP frozen by vacuum alone. You would have to get the pressure to 10 microbar for the BP of NMP to be below the melting point, that is not practially possible in any freeze dryer I know of.
Centrifugal evaporators that can remove NMP are available, however they are expensive and no system, can remove 100% of any solvent. Removing NMP under vacuum requires a good, oil free vacuum pump of the scroll style, a diaphragm pump is not strong enough, a cold trap with sub zero cabability, and a heated system. If you do not heat the pipe work to the trap, the chamber of the system, then NMP will condense in the chamber and pipe work, and damage your evaporation system.
The following application note may help:
https://www.spscientific.com/uploadedFiles/Product_Applications/Genevac/How%20to%20Evaporate%20High%20Boiling%20Point%20Solvents.pdf
If you cannot get access to the necessary equipment for this, then I would seek another solvent that is easier to remove, or, remove NMP via another method replacing it with a solvent that is easier to remove by conventional freeze drying or evaporation.
best of luck
Manish
NMP can be removed during vacuum treatment of sample, maybe using weak heating (I used in different cases 40-100 C). You need to determine the "safe" temperature for the sample. It is also necessary to find a method for determining concentration of residual NMP in a sample.
Water treatment is very undesirable since water is a very polar solvent.
NMP traces can be removed by annealing of samples slightly above 200 C temperature in vacuum. If crystal have higher melting point then it is an appropriate.
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Annealing