Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks
The polymers with hydrophilic moieties typically become soft upon hydration. Here we report an exception to this rule. The modulus was found to increase upon water uptake in polymers in which hydrophilic poly(ethylene glycol) (PEG) segments were incorporated randomly into a chain of hydrophobic segm...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2013
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| Online Access: | https://hdl.handle.net/10356/96573 http://hdl.handle.net/10220/10347 |
| _version_ | 1826114857073639424 |
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| author | Kohn, J. Bedoui, F. Luk, A. Bolikal, D. Murthy, N. S. Widjaja, Leonardus Kresna |
| author2 | School of Materials Science & Engineering |
| author_facet | School of Materials Science & Engineering Kohn, J. Bedoui, F. Luk, A. Bolikal, D. Murthy, N. S. Widjaja, Leonardus Kresna |
| author_sort | Kohn, J. |
| collection | NTU |
| description | The polymers with hydrophilic moieties typically become soft upon hydration. Here we report an exception to this rule. The modulus was found to increase upon water uptake in polymers in which hydrophilic poly(ethylene glycol) (PEG) segments were incorporated randomly into a chain of hydrophobic segments of 3,5-diiodo desaminotyrosyl-tyrosine ethyl ester. The Young's modulus of the copolymer increased by as much as 15-fold upon hydration with 30 to 60 vol% of PEG. This increase in modulus was fully reversible and was observed at both 22 °C and the physiological temperature of 37 °C. A degree of hydration of 3 water molecules per ethylene glycol and hydration-induced phase separation of hydrophilic domains appear to be essential for the observed increase in modulus. This stiffening effect is attributed to the PEG segments in the hydrated domains that no longer participate in the transfer of stress through the polymer matrix as they do when they are molecularly dispersed along the polymer chain in the dry state. |
| first_indexed | 2024-10-01T03:46:02Z |
| format | Journal Article |
| id | ntu-10356/96573 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:46:02Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/965732020-06-01T10:01:33Z Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks Kohn, J. Bedoui, F. Luk, A. Bolikal, D. Murthy, N. S. Widjaja, Leonardus Kresna School of Materials Science & Engineering The polymers with hydrophilic moieties typically become soft upon hydration. Here we report an exception to this rule. The modulus was found to increase upon water uptake in polymers in which hydrophilic poly(ethylene glycol) (PEG) segments were incorporated randomly into a chain of hydrophobic segments of 3,5-diiodo desaminotyrosyl-tyrosine ethyl ester. The Young's modulus of the copolymer increased by as much as 15-fold upon hydration with 30 to 60 vol% of PEG. This increase in modulus was fully reversible and was observed at both 22 °C and the physiological temperature of 37 °C. A degree of hydration of 3 water molecules per ethylene glycol and hydration-induced phase separation of hydrophilic domains appear to be essential for the observed increase in modulus. This stiffening effect is attributed to the PEG segments in the hydrated domains that no longer participate in the transfer of stress through the polymer matrix as they do when they are molecularly dispersed along the polymer chain in the dry state. 2013-06-13T06:54:17Z 2019-12-06T19:32:40Z 2013-06-13T06:54:17Z 2019-12-06T19:32:40Z 2012 2012 Journal Article Bedoui, F., Widjaja, L. K., Luk, A., Bolikal, D., Murthy, N. S., & Kohn, J. (2012). Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks. Soft Matter, 8(7), 2230-2236. 1744-683X https://hdl.handle.net/10356/96573 http://hdl.handle.net/10220/10347 10.1039/c1sm06619f en Soft matter © 2012 The Royal Society of Chemistry. |
| spellingShingle | Kohn, J. Bedoui, F. Luk, A. Bolikal, D. Murthy, N. S. Widjaja, Leonardus Kresna Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title | Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title_full | Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title_fullStr | Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title_full_unstemmed | Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title_short | Anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| title_sort | anomalous increase in modulus upon hydration in random copolymers with hydrophobic segments and hydrophilic blocks |
| url | https://hdl.handle.net/10356/96573 http://hdl.handle.net/10220/10347 |
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