| 1. |
- Golczak, Sebastian, et al.
(författare)
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Comparative XPS surface study of polyaniline thin films
- 2008
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738 .- 1872-7689. ; 179:39, s. 2234-2239
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Tidskriftsartikel (refereegranskat)abstract
- Polyaniline (PANI) films of different thickness have been deposited electrochemically at two different potentials of 0.8 and 1.2 V. Characterization of the surface composition of the material: oxidation states and structural changes have been performed using X-ray photoelectron spectroscopy (XPS). The main findings of this work show that the ratio of the imine to amine nitrogens for thicker films of PANI is close to unity, indicating that the surface layer of PANI is in the emeraldine form (base). On the other hand, the surface of thinner films of PANI contains similar to 14-20% imine nitrogen and similar to 60-70% amine nitrogen. This corresponds to an oxidation state close to that of protoemeraldine. Furthermore, XPS confirms a considerable amount of p-benzoquinone (BQ) as side product formed in all thin samples. The surface morphology examined by electron microscopy measurements shows that thin films have a uniform structure, whereas microporous structure with microchannels and microcaves inside, formed as a non-periodic network of microrods is characteristic for thicker PANI films.
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| 2. |
- Michalska, Agnieszka, et al.
(författare)
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Micro- and Nanostructured Polyaniline for Instant Identification of Metal Ions in Solution
- 2019
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- The unique properties of nanomaterials enable the creation new analytical devices. Polyaniline (PANI) micro- and nanofiber network, freestanding in the gap between two gold microelectrodes, has been used in a new nanodetector for metal ions in solutions. The gold electrodes were modified with the aid of alkanethiols, forming a self-assembled monolayer (SAM), which is able to block the ion current flow, but also to interact with metal ions when specific functional molecules are incorporated into the layer. The electric field of the trapped metal ions induces change of the electrical conductivity of polyaniline nanofibers in vicinity. A small injected sample (75 mu L) of a solution of salt (about 0.5 mu g of salt) was enough to induce a reproducible change in the electrical conductivity of polyaniline nano-network, which was registered as a function of time within 10-20 s. The response was proportional to the concentration of ions. It also depends on properties of ions, e.g., the ionic radius, which allows for identification of metal ions by analyzing the parameters of the signal: the retention time (RT), half width (HW), amplitude (A) and integral intensity (INT). The advantage of the new device is the instant responsiveness and easy operation, but also the simple construction based on organic (polymer) technology. The system is "open"-when learned and calibrated adequately, other metal ions can be analyzed. The nanodetector can be used in cases where monitoring of the presence and concentration of metal ions is important.
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| 3. |
- Golczak, Sebastian, et al.
(författare)
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Degradation of microporous polyaniline film by UV-ozone treatment
- 2009
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Ingår i: POLYMER DEGRADATION AND STABILITY. - : Elsevier BV. - 0141-3910. ; 94:3, s. 350-354
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Tidskriftsartikel (refereegranskat)abstract
- Thin microporous polyaniline films in the emeraldine-base form (PANI-EB) have been prepared electrochemically at a potential of 0.8 V. The effect of ozone treatment on the structural changes of polyaniline thin films has been investigated using X-ray photoelectron spectroscopy, SEM and EPR. Surface analysis showed that oxidation occurs mainly at the carbon atoms, resulting in the formation of C=O and COOH species. The degradation reaction seems to be preferentially directed towards the quinoneimine units. At high extent of carbon oxidation, UV-ozone treatment may involve the direct oxidation of the nitrogen atoms to form -NOx species.
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