Celebrating Soft Matter's 10th Anniversary: Sequential phase transitions in thermoresponsive nanoemulsions
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Doyle_Celebrating soft.pdf
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3.06 MB
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Adobe PDF
Checksum (MD5)
2c43159cf2daf031e4006c5893c63ec8
Author(s)
Doyle, Patrick S.
Hsiao, Lilian
Date Issued
September 2015
Journal
Soft Matter
Publisher
Royal Society of Chemistry
Citation
Hsiao, Lilian C., and Patrick S. Doyle. “Celebrating Soft Matter’s 10th Anniversary: Sequential Phase Transitions in Thermoresponsive Nanoemulsions.” Soft Matter 11, no. 43 (2015): 8426–8431. © The Royal Society of Chemistry 2015
Version
Final published version
Abstract
We report the coexistence of stress-bearing percolation with arrested phase separation in a colloidal system of thermoresponsive nanoemulsions spanning a broad range of volume fractions (0.10 ≤ ϕ ≤ 0.33) and temperatures (22 °C ≤ T ≤ 65 °C). Here, gelation is driven by short-range interdroplet polymer bridging at elevated temperatures. Direct visualization of the gel microstructure shows that nanoemulsions undergo a homogenous percolation transition prior to phase separation. Rheological characterization shows that both the percolated and the phase separated structures are capable of supporting a significant amount of elastic stress. As the system is heated, the sequential onset of these phase transitions is responsible for the unusual two-step increase in the linear viscoelasticity of the gels. In addition, we find that slowing the heating rate significantly reduces the elasticity of the gels at high temperatures. Our results suggest that the formation of metastable gelled states not only depends on the attraction strength and volume fraction of the system, but is also sensitive to the rate at which the attraction strength is increased.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Terms of Use
Creative Commons Attribution-NonCommercial 3.0 Unported licence
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DOI of Published Version
https://doi.org/10.1039/c5sm01581b
