Olsen, Adam P. and Flagan, Richard C. and Kornfield, Julia A. (2006) Manipulation of Athermal Nuclei in Aqueous Poly(ethylene oxide) by Scanning Activity Gravimetric Analysis. Macromolecules, 39 (24). pp. 8419-8427. ISSN 0024-9297. doi:10.1021/ma0614949. https://resolver.caltech.edu/CaltechAUTHORS:20150818-110056580
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Abstract
We show that polymer solutions exhibit memory effects as they undergo repeated dissolution (deliquescence) and crystallization (efflorescence) transitions, similar to those previously observed in polymer melts. These memory effects have been probed using scanning activity gravimetric analysis (SAGA) on aqueous poly(ethylene oxide). SAGA is a new method that enables manipulation of the thermodynamic state of a polymer/solvent system under isothermal conditions. The measurements have been performed on individual micron-sized (∼10 ng) polymer particles that are levitated electrostatically and subjected to programmed changes in the activity of solvent vapor. The particle mass rapidly changes due to sorption or evaporation of solvent in response to changes in vapor activity, providing insights into the changing state of the polymer/solvent system. Repeated cycling of solvent activity within a levitated particle reveals systematic shifts up and down in the deliquescence and efflorescence activities depending upon the extreme activities reached. Melt memory effects have previously been attributed to remnants of lamellar crystals that persist beyond the nominal melting temperature. The present observations suggest that the thickness of these remnants evolves in solution, changing the supersaturation at which they may serve as athermal nuclei. An extension to the classical thermodynamic model of lamellae that includes a reduced interfacial tension at the perimeter of the high energy fold surface predicts the existence of a metastable radius that allows remnants to slowly increase or decrease in thickness under certain conditions, thereby rationalizing the ability to manipulate efflorescence behavior. We also present an analysis that suggests that SAGA can be extended to other polymer/solvent systems with the appropriate choice of temperature.
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| Additional Information: | © 2006 American Chemical Society. Received July 4, 2006. The authors dedicate this paper to Hermann Janeschitz-Kriegl on the occasion of his 82nd birthday and thank him for stimulating this work. The authors also thank Zhen-Gang Wang of the California Institute of Technology for insightful discussions. This material is based upon work supported by the National Science Foundation under Grants 0505393 and 0080065. | |||||||||
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| Issue or Number: | 24 | |||||||||
| DOI: | 10.1021/ma0614949 | |||||||||
| Record Number: | CaltechAUTHORS:20150818-110056580 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20150818-110056580 | |||||||||
| Official Citation: | Manipulation of Athermal Nuclei in Aqueous Poly(ethylene oxide) by Scanning Activity Gravimetric Analysis Adam P. Olsen, Richard C. Flagan, and Julia A. Kornfield Macromolecules 2006 39 (24), 8419-8427 DOI: 10.1021/ma0614949 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 59724 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Irina Meininger | |||||||||
| Deposited On: | 19 Aug 2015 20:57 | |||||||||
| Last Modified: | 10 Nov 2021 22:24 |
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