Resumen: This work shows the preparation of thin films, with thickness from 70 nm to 1 mu m, of meta-polybenzimidazole (m-PBI) on polyimide P84 supports. Ethanolic solutions of m-PBI were used to coat flat and hollow fiber supports of asymmetric P84 with m-PBI in a process where the coating and drying was performed at room temperature. A solution of NaOH in EtOH allowed the dissolution of the m-PBI powder, providing the perfect coating solution to build thin films of m-PBI without damaging the polymeric support. It also meant a green alternative, avoiding the use of toxic solvents, such as dimethylacetamide. The resulting membranes have been tested for the separation of H-2 mixtures at high temperature at different setups to allow checking their reproducibility. With 100 nm thickness the membranes showed their best gas separation performance. For flat membranes at 180 degrees C and 3 bar feed pressure a H-2 permeance of 48.5 GPU was obtained, with respective H-2/CO2 and H-2/N-2 selectivities of 33.3 and 55.8. Besides, the hollow fibers under a feed pressure of 6 bar and tested at the same temperature showed near 90 GPU of H-2 with a H-2/CO2 selectivity of 13.5 in the one-fiber module and over 39 GPU of H-2 with a H-2/CO2 selectivity of 20.2 in the five-fiber module. Finally, the stability of the membranes was proved for 22 days at 180 degrees C. Idioma: Inglés DOI: 10.1002/cssc.202002700 Año: 2021 Publicado en: ChemSusChem 14, 3 (2021), 952-960 ISSN: 1864-5631 Factor impacto JCR: 9.14 (2021) Categ. JCR: GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY rank: 11 / 47 = 0.234 (2021) - Q1 - T1 Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 30 / 180 = 0.167 (2021) - Q1 - T1 Factor impacto CITESCORE: 14.1 - Materials Science (Q1) - Chemical Engineering (Q1) - Energy (Q1) - Environmental Science (Q1)