Ultrafast microwave-enhanced ionothermal synthesis of luminescent crystalline polyimide nanosheets for highly selective sensing of chromium ions

Highly luminescent crystalline polyimide (PI) nanosheets in high yields (up to 95%) were facilely prepared through reaction between melamine and pyromellitic dianhydride via a microwave-enhanced high temperature ionothermal method within only a few minutes (~ 3 min). The as-synthesized luminescent crystalline PI nanosheets have been investigated as sensors for luminescence sensing investigations toward a series of metal ion solutions. Remarkably, such luminescent crystalline PI nanosheets exhibited highly sensitive and selective sensing of chromium ions in aqueous solution, without the interference of other metal ions, such as potassium, calcium, cadmium, plumbum, manganese, mercury, magnesium, cobalt, copper, and zinc.