Molecular Simulations of the Hydration Behavior of a Zwitterion Brush Array and Its Antifouling Property in an Aqueous Environment

Journal Article · 31 January 2018 · Langmuir

DOI: https://doi.org/10.1021/acs.langmuir.7b03386 · OSTI ID:1484351

Xiang, Yuan  ^[1]; Xu, Rong-Guang ^[2]; Leng, Yongsheng  ^[2]

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1. George Washington Univ., Washington, DC (United States). Dept. of Mechanical and Aerospace Engineering
2. George Washington Univ., Washington, DC (United States). Dept. of Mechanical and Aerospace Engineering

We carried out umbrella sampling and molecular dynamics (MD) simulations to investigate molecular interactions between sulfobetaine zwitterions or between sulfobetaine brushes in different media. Simulation results show that it is more energetically favorable for the two sulfobetaine zwitterions or brushes to be fully hydrated in aqueous solutions than in vacuum where strong ion pairs are formed. Structural properties of the hydrated sulfobetaine brush array and its antifouling behavior against a foulant gel are subsequently studied through steered MD simulations. We find that sulfobetaine brush arrays with different grafting densities have different structures and antifouling mechanisms. At a comparably higher grafting density, the sulfobetaine brush array exhibits a more organized structure which can hold a tightly bound hydration water layer at the interface. Compression of this hydration layer results in a strong repulsive force. However, at a comparably lower grafting density, the brush array exhibits a randomly oriented structure in which the antifouling of the brush array is through the deformation of the sulfobetaine branches.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE
• OSTI ID: 1484351
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 6 Vol. 34; ISSN 0743-7463
• Publisher: American Chemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English