1 ethyl 3 methylimidazolium acetate

For the preparation of
cellulose solutions, three types of commercially available materials
have been used: microcrystalline cellulose (MC) from Merck Millipore
with a degree of polymerization (DP) ≈ 210–230 (according
to supplier specification); Avicel PH 101 (Avicel) from Sigma-Aldrich
with DP ≈ 180^{43 (link)} and α–Cellulose
from Sigma-Aldrich with DP ≈ 780.^{44 (link)} The room temperature ionic liquids 1-ethyl-3-methylimidazolium acetate
([Emim][OAc]) and 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]),
both in BASF quality (≥95%), have been purchased from Sigma-Aldrich.
The ionic liquids and the cellulose materials are both hygroscopic.
[Emim][OAc] and [Bmim][OAc] water content was ≤1.1% according
to supplier specification. Because in our previous works we had demonstrated
that traces of water do not hinder cellulose solubilization and do
not have a negative impact to the phase separation process,^{45 (link)} all materials were used as received. Further
on, we considered that this may also facilitate the up-scaling if
desired. Dimethylsulfoxide (DMSO; analytical reagent, assay ≥99.5%)
from VWR International was used as co-solvent for cellulose dissolution.
The precipitation of the porous films was performed in water purified
with a Merck–Millipore purification system and having a resistivity
of ∼18.2 MΩ^.cm and a TOC value below 5 ppm.

The ionic liquid, 1-ethyl-3-methylimidazolium
acetate, and 97% ([EMIM][OAc]) were purchased from Sigma-Aldrich.
Anhydrous manganese acetate, 98%, was purchased from Alfa Aesar. The
ionic liquid was vacuum dried at 90 °C for 12 h prior to use.
All chemicals were stored in an inert nitrogen atmosphere glovebox.