Wettability behavior of DTMS modified SiO2: Experimental and molecular dynamics study

Chen-Xiang Wang; Ning Wang; Xu-Sheng Li; Xue-Fen Zhang

doi:10.1016/j.jmgm.2024.108786

Wettability behavior of DTMS modified SiO₂: Experimental and molecular dynamics study

J Mol Graph Model. 2024 May 2:130:108786. doi: 10.1016/j.jmgm.2024.108786. Online ahead of print.

Authors

Chen-Xiang Wang¹, Ning Wang², Xu-Sheng Li², Xue-Fen Zhang³

Affiliations

¹ Transportation Institute, Inner Mongolia Engineering Research Center for Intelligent Transportation Equipment, Inner Mongolia University, Hohhot, 010021, China; State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310027, China.
² Transportation Institute, Inner Mongolia Engineering Research Center for Intelligent Transportation Equipment, Inner Mongolia University, Hohhot, 010021, China.
³ Transportation Institute, Inner Mongolia Engineering Research Center for Intelligent Transportation Equipment, Inner Mongolia University, Hohhot, 010021, China. Electronic address: xfzhang@imu.edu.cn.

PMID: 38710130
DOI: 10.1016/j.jmgm.2024.108786

Abstract

In this research, the wetting behavior of SiO₂ modified with dodecyltrimethoxysilane (DTMS) was explored using both experimental and molecular dynamics (MD) simulation approaches. The experimental results reveal that DTMS can chemically bond to the SiO₂ surface, and the contact angle (CA) reaches the maximum value of 157.7° when the mass of DTMS is twice that of SiO₂. The different wetting behaviors caused by DTMS grafting were analyzed by CA fitting, ionic pairs, concentration distribution, molecule orientation, and interfacial interaction energy. The results demonstrate that a 25 % DTMS grafting rate resulted in a maximum CA of 158.2°, which is ascribed to the disruption of interfacial hydrogen bonding and changes in the hydration structure caused by DTMS grafting. Moreover, the above hydrophobic SiO₂ model shows a slight decrease in CA as the water temperature increases, which is consistent with the experimental findings. In contrast, an opposite change was observed for the pristine SiO₂ model. Although the higher water temperature enhances the diffusion capacity of water molecules in both models, the difference in interfacial interactions is responsible for the change in CA. We hope this finding will contribute to a deeper understanding of the wetting adjustment of SiO₂.

Keywords: Grafting rate; Hot water repellency; Molecular dynamics; SiO(2); Superhydrophobic.