The Structure of Water in Silica Mesopores – Influence of the Pore Wall Polarity

Weinberger C, Zysk F, Hartmann M, Kaliannan NK, Keil W, Kühne TD, Tiemann M (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Advanced Materials Interfaces WILEY-VCH Verlag GmbH & Co. KGaA

Book Volume: 9

Article Number: 2200245

Journal Issue: 20

DOI: 10.1002/admi.202200245

Abstract

In the spatial confinement of cylindrical mesopores with diameters of a few nanometers, water molecules experience restrictions in hydrogen bonding. This leads to a different behavior regarding the molecular orientational freedom (‘structure of water') compared to the bulk liquid state. In addition to the pore size, the behavior is also strongly affected by the strength of the pore wall-to-water interactions, that is, the pore wall polarity. In this work, this is studied both experimentally and theoretically. The surface polarity of mesoporous silica (SiO2) is modified by functionalization with trimethylsilyl moieties, resulting in a change from a hydrophilic (pristine) to a hydrophobic pore wall. The mesopore surface is characterized by N2 and H2O sorption experiments. Those results are combined with IR spectroscopy to investigate pore wall-to-water interactions leading to different structures of water in the mesopore. Furthermore, the water's structure is studied theoretically to gain deeper insight into the interfacial interactions. For this purpose, the structure of water is analyzed by pairing densities, coordination, and angular distributions with a novel adaptation of surface-specific sum-frequency generation calculation for pore environments.

Involved external institutions

Universität Paderborn DE Germany (DE)

How to cite

APA:

Weinberger, C., Zysk, F., Hartmann, M., Kaliannan, N.K., Keil, W., Kühne, T.D., & Tiemann, M. (2022). The Structure of Water in Silica Mesopores – Influence of the Pore Wall Polarity. Advanced Materials Interfaces, 9(20). https://doi.org/10.1002/admi.202200245

MLA:

Weinberger, Christian, et al. "The Structure of Water in Silica Mesopores – Influence of the Pore Wall Polarity." Advanced Materials Interfaces 9.20 (2022).

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