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Thermodynamische Modellierung des Quellverhaltens von stimuli-responsiven Gelen in Mehrkomponentensystemen mit PC-SAFT
Citation Link: https://doi.org/10.15480/882.4632
Publikationstyp
Master Thesis
Date Issued
2021-04-05
Sprache
German
Author(s)
Referee
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2021-04-16
Institut
TORE-DOI
Citation
Technische Universität Hamburg (2021)
Despite being versatile materials of major interest, stimuli-responsive gels have few
actual application examples, due to missing insights in the thermodynamics of the
response behaviour. For this reason, various experimental and theoretical
investigations of the swelling behavior of poly (N-isopropylacrylamide) (PNIPAAm)
gels in different solvents were carried out during this work to improve the
understanding of the polymer solvent interactions.
Within the experimental investigations, swelling behavior of PNIPAAm was
measured in binary gel-solvent systems. Positive swelling behavior of PNIPAAm in
the solvents water, butanol and acetic acid was shown. In contrast only low degrees of
swelling were determined in the hydrophobic solvents hexane and butyl acetate. The
reason was found in the different occurring interactions between gel and solvent.
While hydrophilic solvents can form strong hydrophilic interactions with the amide
groups of the gel, the weak hydrophobic interactions predominate in hydrophobic
solvents. These experiments were supplemented by theoretical studies using the
equation of state PC-SAFT, which was implemented and validated in Python during
this work. Within these studies, a predictive utilization of the model could only be
obtained for the solvents acetic acid and butanol. The swelling degree of PNIPAAm in
the hydrophilic solvents generally showed very good agreement to the experimental
data by adapting the binary interaction parameter. In contrast, modeling of the poor
swelling behavior in the hydrophobic solvents results in greater deviations. The final
application of the model to multi-component systems showed a general applicability
but also the complexity of modelling polymer systems. During these investigations,
the negative response behaviour of the gel with increasing hexane content of
experimental data can be obtained in the simulation. Contrary to that, the model
showed a trend opposite to the experimental data for increasing butyl acetate content.
actual application examples, due to missing insights in the thermodynamics of the
response behaviour. For this reason, various experimental and theoretical
investigations of the swelling behavior of poly (N-isopropylacrylamide) (PNIPAAm)
gels in different solvents were carried out during this work to improve the
understanding of the polymer solvent interactions.
Within the experimental investigations, swelling behavior of PNIPAAm was
measured in binary gel-solvent systems. Positive swelling behavior of PNIPAAm in
the solvents water, butanol and acetic acid was shown. In contrast only low degrees of
swelling were determined in the hydrophobic solvents hexane and butyl acetate. The
reason was found in the different occurring interactions between gel and solvent.
While hydrophilic solvents can form strong hydrophilic interactions with the amide
groups of the gel, the weak hydrophobic interactions predominate in hydrophobic
solvents. These experiments were supplemented by theoretical studies using the
equation of state PC-SAFT, which was implemented and validated in Python during
this work. Within these studies, a predictive utilization of the model could only be
obtained for the solvents acetic acid and butanol. The swelling degree of PNIPAAm in
the hydrophilic solvents generally showed very good agreement to the experimental
data by adapting the binary interaction parameter. In contrast, modeling of the poor
swelling behavior in the hydrophobic solvents results in greater deviations. The final
application of the model to multi-component systems showed a general applicability
but also the complexity of modelling polymer systems. During these investigations,
the negative response behaviour of the gel with increasing hexane content of
experimental data can be obtained in the simulation. Contrary to that, the model
showed a trend opposite to the experimental data for increasing butyl acetate content.
DDC Class
660: Technische Chemie
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