Characterization of a Cation-Exchange/Polyaniline Composite Membrane
Bibliographic record
Abstract
A composite membrane was prepared by chemical polymerization of a thin layer of polyaniline (PANI) in the presence of high oxidant concentration on a single face of a sulfonated cation-exchange membrane (Neosepta CMX from Tokuyama Soda Inc.). The CMX−PANI composite membrane was characterized as a function of the polymerization time by cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), and ion-exchange capacity (IEC) measurements. CV and XPS results demonstrate that, under our experimental conditions, the maximum PANI loading is attained after 1 h of polymerization. This is accompanied by a decrease in membrane ion-exchange capacity due to the presence of the cationic PANI acting as counterions for the sulfonate groups of the membrane. The optimal membrane permselectivity for protons against bivalent metallic cations (Zn 2+ and Cu 2+ ) was also found at a polymerization time of 1 h. In fact, at longer polymerization times, XPS data indicate the occurrence of PANI degradation. UV−visible spectroscopy confirmed the presence of benzoquinone, the major degradation product of PANI, in the solution used for the oxidation of aniline into polyaniline. Correlating XPS and IEC results with permselectivity of the composite membrane let us believe that although some small amount of PANI is still present at the surface and within the membrane, it is not sufficient to maintain good permselectivity properties. To create an effective blocking barrier to the bivalent cations, the PANI layer formed at the surface of the CMX membrane needs to be sufficiently thick and uniform.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".