| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Baldursdottir, Stefania G.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (8/8 displayed)
- 2017The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous matscitations
- 2017The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous matscitations
- 2017Molecular weight-dependent degradation and drug release of surface-eroding poly(ethylene carbonate)citations
- 2015Simple measurements for prediction of drug release from polymer matrices - Solubility parameters and intrinsic viscositycitations
- 2015Rheology as a tool for evaluation of melt processability of innovative dosage formscitations
- 2014Property profiling of biosimilar mucus in a novel mucus-containing in vitro model for assessment of intestinal drug absorptioncitations
- 2013Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysiscitations
- 2005Rheological characterization and turbidity of riboflavin-photosensitized changes in alginate/GDL systemscitations
Places of action
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article
Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis
Abstract
The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity.