Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH
The swelling of polyelectrolyte hydrogels usually depends on the pH, and if the pH is high enough degradation can occur. A microindentation device was developed to dynamically test these processes in whey protein isolate hydrogels at alkaline pH 7–14. At low alkaline pH the shear modulus decreases d...
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| Format: | Article |
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MDPI AG
2017-11-01
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| Series: | Gels |
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| Online Access: | https://www.mdpi.com/2310-2861/3/4/44 |
| _version_ | 1819209280492929024 |
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| author | Wei Hu Francois Martin Romain Jeantet Xiao Dong Chen Ruben Mercadé-Prieto |
| author_facet | Wei Hu Francois Martin Romain Jeantet Xiao Dong Chen Ruben Mercadé-Prieto |
| author_sort | Wei Hu |
| collection | DOAJ |
| description | The swelling of polyelectrolyte hydrogels usually depends on the pH, and if the pH is high enough degradation can occur. A microindentation device was developed to dynamically test these processes in whey protein isolate hydrogels at alkaline pH 7–14. At low alkaline pH the shear modulus decreases during swelling, consistent with rubber elasticity theory, yet when chemical degradation occurs at pH ≥ 11.5 the modulus decreases quickly and extensively. The apparent modulus was constant with the indentation depth when swelling predominates, but gradients were observed when fast chemical degradation occurs at 0.05–0.1 M NaOH. In addition, these profiles were constant with time when dissolution rates are also constant, the first evidence that a swollen layer with steady state mechanical properties is achieved despite extensive dissolution. At >0.5 M NaOH, we provide mechanical evidence showing that most interactions inside the gels are destroyed, gels were very weak and hardly swell, yet they still dissolve very slowly. Microindentation can provide complementary valuable information to study the degradation of hydrogels. |
| first_indexed | 2024-12-23T05:52:46Z |
| format | Article |
| id | doaj.art-11ab5271dbd8416fa8a9c3765c95674a |
| institution | Directory Open Access Journal |
| issn | 2310-2861 |
| language | English |
| last_indexed | 2024-12-23T05:52:46Z |
| publishDate | 2017-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Gels |
| spelling | doaj.art-11ab5271dbd8416fa8a9c3765c95674a2022-12-21T17:57:54ZengMDPI AGGels2310-28612017-11-01344410.3390/gels3040044gels3040044Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pHWei Hu0Francois Martin1Romain Jeantet2Xiao Dong Chen3Ruben Mercadé-Prieto4Suzhou Key Laboratory of Green Chemical Engineering, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, ChinaScience et Technologie du Lait et de l’Oeuf (STLO), Agrocampus Ouest, INRA, 35000 Rennes, FranceScience et Technologie du Lait et de l’Oeuf (STLO), Agrocampus Ouest, INRA, 35000 Rennes, FranceSuzhou Key Laboratory of Green Chemical Engineering, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, ChinaSuzhou Key Laboratory of Green Chemical Engineering, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, ChinaThe swelling of polyelectrolyte hydrogels usually depends on the pH, and if the pH is high enough degradation can occur. A microindentation device was developed to dynamically test these processes in whey protein isolate hydrogels at alkaline pH 7–14. At low alkaline pH the shear modulus decreases during swelling, consistent with rubber elasticity theory, yet when chemical degradation occurs at pH ≥ 11.5 the modulus decreases quickly and extensively. The apparent modulus was constant with the indentation depth when swelling predominates, but gradients were observed when fast chemical degradation occurs at 0.05–0.1 M NaOH. In addition, these profiles were constant with time when dissolution rates are also constant, the first evidence that a swollen layer with steady state mechanical properties is achieved despite extensive dissolution. At >0.5 M NaOH, we provide mechanical evidence showing that most interactions inside the gels are destroyed, gels were very weak and hardly swell, yet they still dissolve very slowly. Microindentation can provide complementary valuable information to study the degradation of hydrogels.https://www.mdpi.com/2310-2861/3/4/44whey proteinindentationshear modulusswellingdissolution |
| spellingShingle | Wei Hu Francois Martin Romain Jeantet Xiao Dong Chen Ruben Mercadé-Prieto Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH Gels whey protein indentation shear modulus swelling dissolution |
| title | Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH |
| title_full | Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH |
| title_fullStr | Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH |
| title_full_unstemmed | Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH |
| title_short | Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH |
| title_sort | micromechanical characterization of hydrogels undergoing swelling and dissolution at alkaline ph |
| topic | whey protein indentation shear modulus swelling dissolution |
| url | https://www.mdpi.com/2310-2861/3/4/44 |
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