Fluorination Increases Hydrophobicity at the Macroscopic Level but not at the Microscopic Level
Weishuai Di1, Xin Wang1, Yanyan Zhou1, Yuehai Mei2, Wei Wang2,3,4*, and Yi Cao1,2,3,4*
1Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China 2Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China 3Institute for Brain Sciences, Nanjing University, Nanjing 210093, China 4Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing 210093, China
Abstract：Hydrophobic interactions have been studied before in detail based on hydrophobic polymers, such as polystyrene (PS). Because fluorinated materials have relatively low surface energy, they often show both oleophobicity and hydrophobicity at the macroscopic level. However, it remains unknown how fluorination of hydrophobic polymer influences hydrophobicity at the microscopic level. We synthesized PS and fluorine-substituted PS (FPS) by employing the reversible addition-fragmentation chain transfer polymerization method. Contact angle measurements confirmed that FPS is more hydrophobic than PS at the macroscopic level due to the introduction of fluorine. However, single molecule force spectroscopy experiments showed that the forces required to unfold the PS and FPS nanoparticles in water are indistinguishable, indicating that the strength of the hydrophobic effect that drives the self-assembly of PS and FPS nanoparticles is the same at the microscopic level. The divergence of hydrophobic effect at the macroscopic and microscopic level may hint different underlying mechanisms: the hydrophobicity is dominated by the solvent hydration at the microscopic level and the surface-associated interaction at the macroscopic level.
(Spectroscopic and microscopic techniques in biophysics and medical physics)
引用本文:
. [J]. 中国物理快报, 2022, 39(3): 38701-038701.
Weishuai Di, Xin Wang, Yanyan Zhou, Yuehai Mei, Wei Wang, and Yi Cao. Fluorination Increases Hydrophobicity at the Macroscopic Level but not at the Microscopic Level. Chin. Phys. Lett., 2022, 39(3): 38701-038701.
2022, Vol. 39 
