Co-Nonsolvency Transition of Poly(N-isopropylacrylamide) Brushes in a Series of Binary Mixtures
Yong H, Bittrich E, Uhlmann P, Fery A, Sommer JU (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 52
Pages Range: 6285-6293
Journal Issue: 16
DOI: 10.1021/acs.macromol.9b01286
Abstract
Co-nonsolvency occurs if a mixture of two good solvents causes the collapse or demixing of polymers into a polymer-rich phase in a certain range of compositions of these two solvents. In this work, we systematically study the co-nonsolvency behavior of poly(N-isopropylacrylamide) brushes of different grafting densities in a series of alcohol-water binary mixtures with increasing hydrophobic parts ranging from methanol to 1-butanol by using ellipsometry. We report a strong collapse transition by increasing the alcohol concentration in the water-rich phase, which is enhanced for longer-chain alcohols. The analysis of the thermodynamic properties of the alcohol-water series displays that an increasing demixing tendency between alcohol and water is correlated with an enhancement of the collapse transition of the brush. The increase of grafting density weakens the transition behavior but does not shift the solvent composition point of maximum brush collapse, which is in agreement with the predictions of a recently proposed mean-field model based on the preferential adsorption concept. Among the fully miscible solvents, the most sensitive switching behavior of the brush is found for 1-propanol while 1-butanol already displays a miscibility gap at higher volume fractions.
Involved external institutions
Germany (DE)How to cite
APA:
Yong, H., Bittrich, E., Uhlmann, P., Fery, A., & Sommer, J.-U. (2019). Co-Nonsolvency Transition of Poly(N-isopropylacrylamide) Brushes in a Series of Binary Mixtures. Macromolecules, 52(16), 6285-6293. https://doi.org/10.1021/acs.macromol.9b01286
MLA:
Yong, Huaisong, et al. "Co-Nonsolvency Transition of Poly(N-isopropylacrylamide) Brushes in a Series of Binary Mixtures." Macromolecules 52.16 (2019): 6285-6293.
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