Journal article
Tuning the thermostability of GHG gels by salts at different positions on the Hofmeister scale
Scientific reports, v 14(1), 14742
26 Jun 2024
PMID: 38926473
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The influence of Hofmeister cations (NH
4
+
, Na
+
, Mg
2+
) and anions (H
2
PO
4
−
, CH
3
COO
−
, Cl
−
,
NO
3
−
) on the thermostability of a GHG hydrogel was investigated. The combined results of UV circular dichroism (UVCD) and Small Amplitude Oscillatory Shear Rheology experiments reveal that the addition of salt reduces the stability of the gel phase and the underlying fibrils. In line with the cationic Hofmeister hierarchy, the chaotropic Mg
2+
ions caused the greatest thermal destabilization of the gel phase with the gel → sol transition temperature
T
gs
value lowered by 10 °C. In the absence of salt, the gel → sol transition probed by the storage modulus and microscopy is biphasic. In the presence of salt, it becomes monophasic. Contrary to expectations the presence of Hofmeister anions leads to a nearly identical reduction of the gel → sol transition temperatures. However, UVCD spectra suggest that they affect the ππ-stacking between imidazole groups to a different extent. We relate the absence of ion specificity regarding the solubility of fibrils (probed by UVCD) to the observed enthalpy-entropy compensation of the dissolution process. Our results combined show how CD spectroscopy and rheology combined yields a more nuanced picture of the processes underlying the gel → sol transition.
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Details
- Title
- Tuning the thermostability of GHG gels by salts at different positions on the Hofmeister scale
- Creators
- Nichole S. O’Neill - Drexel UniversityNicolas J. Alvarez - Drexel UniversityReinhard Schweitzer-Stenner - Drexel University
- Publication Details
- Scientific reports, v 14(1), 14742
- Publisher
- Nature Publishing Group UK
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]; Chemical and Biological Engineering; Chemistry
- Web of Science ID
- WOS:001259483400004
- Scopus ID
- 2-s2.0-85197133417
- Other Identifier
- 991021889579904721
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- Web of Science research areas
- Chemistry, Physical