Transformation of iron oxides on PI electrospun membranes

Route to a Porous Carbon Nanofiber Membrane Containing FexCy/Fe by Facile In Situ Ion-Exchange Functionalization of the PAA Carboxyl Group: Exemplified by a Supercapacitor

“…In addition, some particles were clearly observed on the surface of PI-Fe nanofibers. It is speculated that iron-related species were generated owing to the ion-exchange of Fe 3+ . The elemental mapping images of PI-Fe are shown in Figure e–h, where the C, N, O, and Fe elements were detected with a uniform distribution and the apparent content of the Fe element was about 2.8 wt % according to the results of the EDS spectrum (Figure S3a and Table S1).…”

“…On the other hand, poly­(amic acid) (PAA) contains a large number of carboxyl groups, which can be utilized as good assembly templates for copper ions, silver ions, − and so forth. Li et al obtained a PI composite fiber membrane loaded with α-Fe 2 O 3 /Fe 3 O 4 by ion exchange of PAA and Fe 3+ , imidization, and hydrogen reduction, showing a good magnetic response. Unfortunately, this work did not study the functional modification of PI-based carbon nanofibers by metal ions, which still has great potential.…”

A review on electrospun magnetic nanomaterials: methods, properties and applications

“…6(a) shows an example of such surface topology. Polymers are electrospun to form fibres and then MNPs are coated onto the fibres either by in situ synthesis 109,143 or post-spinning deposition. 107,108,112 Both approaches face the issue of aggregation, however, there have been few research efforts focused on resolving this problem.…”

“…107,108,112 Both approaches face the issue of aggregation, however, there have been few research efforts focused on resolving this problem. 107,110,143 In one notable example, in situ synthesis was studied, focussing on the influence of drying mode on the morphology of iron oxides upon polyimide (PI) NFs. 143 This study concluded that drying under vacuum was more effective than drying in air to allow for uniform particle distribution.…”

“…107,110,143 In one notable example, in situ synthesis was studied, focussing on the influence of drying mode on the morphology of iron oxides upon polyimide (PI) NFs. 143 This study concluded that drying under vacuum was more effective than drying in air to allow for uniform particle distribution. When using the deposition method, specific techniques are used to provide uniform distribution of the MNPs.…”