Rheological Control of Microemulsions via Multifunctional Thermoresponsive Polymer Surfactants
Final Report Abstract
This project aimed at a temperature control of the rheological properties of oil-in-water (OW) microemulsion by admixture of amphiphilic thermoresponsive block copolymers. Normally, these properties become controlled by polymer surfactants of BAB-triblock architecture (with A = long hydrophilic “bola”- and B = short hydrophobic “anchor” block). However, the viscosity of such modified microemulsions typically decreases substantially with increasing temperature. For counteracting this behaviour, one of the B-blocks became substitute by a thermoresponsive B*-block in this project. With increasing temperature, the B*-block will pass through an LCST-phase transition and switch from hydrophilic to hydrophobic, thus leading to a self-assembled network structure with a concomitant increase of viscosity. For that purpose, amphiphilic block copolymers with thermoresponsive segments were synthesised with systematic variation of architecture and LCST-monomer. Their solutions in water and in OW microemulsions were investigated with respect to their flow behaviour and the contained structures as a function of temperature. The structural characterisation was done in particular by application of light and neutron scattering, was well as by cryogenic transmission electron microscopy and fluorescence methods. The combination of these results showed that our concept of mixed permanent and switchable hydrophobic anchoring blocks allowed both, to control the temperature-dependent aggregation of the polymer surfactants as well as the rheological properties. This means that via the specific copolymer architecture, the normal reduction of viscosity with rising temperature can be suppressed and one may even achieve a viscosity increase. Our investigations showed a strong dependence of this effect on the architecture of the copolymers employed and of the type of LCST-block. Above a certain characteristic temperature (LCST), these blocks form new hydrophobic domains, whose interconnection explains the observed viscosity increase. In summary, we have demonstrated here a functioning concept for the controlled increase of viscosity upon rising temperature, where the change of viscosity as a function of temperature can be controlled by choice of the amphiphilic copolymers. The basic concept demonstrated here should be applicable more generally and become transferred to other aqueous systems of interest.
Publications
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Thermoresponsive Block Copolymers from One-Pot Sequential RAFT Polymerizations and their Self- Assembly in Aqueous Solution. 14th European Detergency Conference EDC, 10.10.2018, Berlin
M. Hechenbichler, C. Henschel, C. Herfurth, A. Laschewsky, B. von Lospichl & M. Gradzielski
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Controlling Self-Assembly of Thermo-responsive Amphiphilic Block Copolymers by Variation Chemical Structure and Architecture. Polydays 2019: Polymer Science and Engineering in View of Digitalization, 11- 13.09.2019, Berlin
M. Hechenbichler, M. Gradzielski, C. Henschel, A. Laschewsky, B. von Lospichl & A. Prause
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Influence of Chemical Structure and Architecture on Self-Assembly of Thermo-responsive Amphiphilic Block Copolymers. 49th Biennial Meeting of the German Colloid Society, Congress on "Complex Fluids", 23-25.09.2019, Stuttgart.
M. Hechenbichler, M. Gradzielski, C. Henschel, A. Laschewsky, B. von Lospichl & A. Prause
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Self-Assembly of Thermo-responsive Amphiphilic Block Copolymers. 15th European Detergency Conference EDC, 23.10.2019, Berlin.
M. Hechenbichler, C. Henschel, B. von Lospichl, A. Prause, M. Gradzielski & A. Laschewsky
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Structural Investigation of Thermo-responsive Block Copolymers with Microemulsions in Water. 15th European Detergency Conference EDC, 23.10.2019, Berlin
A. Prause, M. Hechenbichler, B. von Lospichl, A. Laschewsky & M. Gradzielski
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Poly(N,N-bis(2-methoxyethyl)acrylamide), a thermoresponsive non-ionic polymer combining the amide and the ethyleneglycolether motifs. Colloid and Polymer Science, 299(2), 205-219.
Hechenbichler, Michelle; Laschewsky, André & Gradzielski, Michael
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Self-Assembly of Thermo-responsive Block Copolymers with Varying Chemical Structure and Architecture. Makromolekulares Kolloquium Freiburg, 26-28.02.2020, Freiburg.
M. Hechenbichler, M. Gradzielski, C. Henschel, A. Laschewsky, B. von Lospichl & A. Prause
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A Fluorescence Study on the Self-Assembly of Thermo-responsive Amphiphilic Block Copolymers. 32. Tag der Chemie des Verbands der Chemischen Industrie VCI Nordost, 06.07.2021, Universität Potsdam, Potsdam
M. Hechenbichler, M. Gradzielski & A. Laschewsky
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Interaction of microemulsion droplets with hydrophobically modified thermo-responsive blockpolymers. 15th European Detergency Conference EDC (virtual), 13.10.2021, Berlin
A. Prause, M. Hechenbichler, R. F. Schmidt, A. Laschewsky & M. Gradzielski
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Network vs. Flowers: A Fluorescence Study on the Self-Assembly of Thermo-responsive Amphiphilic Block Copolymers. Makromolekulares Kolloquium Freiburg, 26.02.2021 (Virtual), Freiburg.
M. Hechenbichler, M. Gradzielski & A. Laschewsky
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Self-Assembly of Thermo-responsive Associative Thickener Block Copolymers. 2nd Virtual Polymer Conference 19-21.04.2021, organized by Åbo Akademi University (Finland).
A. Laschewsky, M. Hechenbichler, A. Prause & M. Gradzielski
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Thermoresponsive Self-Assembly of Twofold Fluorescently Labeled Block Copolymers in Aqueous Solution and Microemulsions. Langmuir, 38(17), 5166-5182.
Hechenbichler, Michelle; Prause, Albert; Gradzielski, Michael & Laschewsky, André
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Aggregation Behavior of Nonsymmetrically End-Capped Thermoresponsive Block Copolymers in Aqueous Solutions: Between Polymer Coils and Micellar States. Macromolecules, 55(13), 5849-5863.
Prause, Albert; Hechenbichler, Michelle; von Lospichl, Benjamin; Feoktystov, Artem; Schweins, Ralf; Mahmoudi, Najet; Laschewsky, André & Gradzielski, Michael
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Exploring Thermoresponsivity and Co-nonsolvency beyond Poly(N-isopropylacrylamide). 105th Canadian Chemistry Conference & Exhibition CCCE 2022, 13-17.06.2022, Calgary (Alberta, Canada).
A. Laschewsky, M. Gradzielski, P. Müller-Buschbaum & C. M. Papadakis
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Rheological Control of Aqueous Dispersions by Different Types of Thermo-responsive BAB* Copolymers. 51st Biennial Assembly of the German Colloid Society, 28-30.09.2022, Berlin.
A. Prause, M. Hechenbichler, R. F. Schmidt, A. Laschewsky & M. Gradzielski
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Rheological Control of Aqueous Dispersions by Thermoresponsive BAB* Copolymers of Different Architectures. Macromolecules, 56(1), 104-121.
Prause, Albert; Hechenbichler, Michelle; Schmidt, Robert F.; Simon, Miriam; Prévost, Sylvain; Cavalcanti, Leide P.; Talmon, Yeshayahu; Laschewsky, André & Gradzielski, Michael
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Thermo-responsive Polymeric Amphiphiles as "Smart" Rheology Modifiers for Aqueous Solution and Microemulsions. 18th European Detergency Conference EDC, 26.10.2022, Berlin.
A. Laschewsky, M. Hechenbichler, A. Prause & M. Gradzielski
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Improving the Rheological Properties of microemulsion droplets using thermo-responsive blockpolymers. 18th Zsigmondy Colloquium 2023, 4-6. April 2023, Berlin.
A. Prause, M. Hechenbichler, R. F. Schmidt, A. Laschewsky & M. Gradzielski
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Modifying Rheological Properties of Microemulsion Droplets through the Use of Thermoresponsive Block Copolymers. 19th European Detergency Conference EDC, 25.10.2023, Berlin
A. Prause, M. Hechenbichler, R. F. Schmidt, A. Laschewsky & M. Gradzielski
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Modifying the Properties of Microemulsion Droplets by Addition of Thermoresponsive BAB* Copolymers. Langmuir, 39(5), 2022-2035.
Prause, Albert; Hechenbichler, Michelle; Schmidt, Robert F.; Prévost, Sylvain; Cavalcanti, Leide P.; Laschewsky, André & Gradzielski, Michael
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Phase behavior and structure of a biocompatible microemulsion based on Tween 20, 2-ethylhexylglycerine and isopropyl palmitate in water. Colloid and Polymer Science, 301(7), 753-762.
Schmidt, Robert Franz; Prause, Albert; Prévost, Sylvain; Doutch, James & Gradzielski, Michael
