Single-molecule Study Reveals that Sodium Alginate is Hydrophobic

Chen-Xi Gu; Rui-Xue Li; Wen-Tao Yuan; Jiu-Long Zhou; Yu-Xi Duan; Yu Bao; Shu-Xun Cui

doi:10.1007/s10118-025-3277-y

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Single-molecule Study Reveals that Sodium Alginate is Hydrophobic

RESEARCH ARTICLE | Updated：2025-02-25

- Single-molecule Study Reveals that Sodium Alginate is Hydrophobic
- Single-molecule Study Reveals that Sodium Alginate is Hydrophobic
- 高分子科学（英文） 2025年43卷第3期页码：439-446
- Affiliations：
  
  School of Chemistry, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
- Author bio：
  
  baoyu@swjtu.edu.cn (Y.B.)
  cuishuxun@swjtu.edu.cn (S.X.C.)
- Funds：
  
  This work was financially supported by the National Natural Science Foundation of China (No. 22273079).;Electronic supplementary information (ESI) is available free of charge in the online version of this article at http://doi.org/10.1007/s10118-025-3277-y.
- DOI：10.1007/s10118-025-3277-y
  中图分类号：
- 收稿日期：2024-10-30，
  
  修回日期：2024-11-19，
  
  录用日期：2024-11-27，
  
  网络出版日期：2025-01-20，
  
  纸质出版日期：2025-03-01
- Accepted：
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Gu, C. X.; Li, R. X.; Yuan, W. T.; Zhou, J. L.; Duan, Y. X.; Bao, Y.; Cui, S. X. Single-molecule study reveals that sodium alginate is hydrophobic. Chinese J. Polym. Sci. 2025, 43, 439–446

Chen-Xi Gu, Rui-Xue Li, Wen-Tao Yuan, et al. Single-molecule Study Reveals that Sodium Alginate is Hydrophobic[J]. Chinese journal of polymer science, 2025, 43(3): 439-446.
Gu, C. X.; Li, R. X.; Yuan, W. T.; Zhou, J. L.; Duan, Y. X.; Bao, Y.; Cui, S. X. Single-molecule study reveals that sodium alginate is hydrophobic. Chinese J. Polym. Sci. 2025, 43, 439–446 DOI： 10.1007/s10118-025-3277-y.

Chen-Xi Gu, Rui-Xue Li, Wen-Tao Yuan, et al. Single-molecule Study Reveals that Sodium Alginate is Hydrophobic[J]. Chinese journal of polymer science, 2025, 43(3): 439-446. DOI： 10.1007/s10118-025-3277-y.

摘要

SMFS study reveals that hydrophobic effects are key to the long plateau observed in the experimental curve of SA obtained in water

while electrostatic repulsion between carboxylate groups leads to greater rigidity than its inherent elasticity. The hydrophobicity of SA offers new insights into its gelation mechanism in water.

Abstract

Sodium alginate (SA) is generally considered highly hydrophilic due to two hydroxyl groups and a carboxylate group on each pyranose ring. However

SA will form a gel after dissolving in water for a certain period. The two properties of SA

hydrophilicity and gelation

seem to be paradoxical. In this study

to explore the mechanism behind these paradoxical properties

the single-chain behaviors of SA in various liquid environments have been investigated by using single-molecule force spectroscopy (SMFS). In nonpolar solvents such as nonane

SA exhibits its single-chain inherent elasticity consistent with the theoretical elasticity derived from quantum mechanical (QM) calculations. Notably

the experimental curve of SA obtained in water shows a long plateau in the low force region. Further research reveals that this phenomenon is driven by the hydrophobic effect. Additionally

SA shows greater rigidity than its inherent elasticity in the middle and high force regions due to electrostatic repulsion between carboxylate groups on adjacent sugar rings. Comparative single-molecule studies suggest that SA exhibits considerable hydrophobicity

offering new insights into the gelation process in water.

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references

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