The effect of guanidinium functionalization on the structural properties and anion affinity of polyelectrolyte multilayers

Journal article (2015)

Authors

Z. Cao OLD ChemE/Organic Materials and Interfaces
PI Gordiichuk External organisation
K Loos External organisation
Ernst J. R. Sudhölter OLD ChemE/Organic Materials and Interfaces
L.C.P.M. de Smet OLD ChemE/Organic Materials and Interfaces
Research Group
OLD ChemE/Organic Materials and Interfaces
More Info
expand_more

Published Date

2015

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Research Group

OLD ChemE/Organic Materials and Interfaces

Abstract

Poly(allylamine hydrochloride) (PAH) is chemically functionalized with guanidinium (Gu) moieties in water at room temperature. The resulting PAH-Gu is used to prepare polyelectrolyte multilayers (PEMs) with poly(sodium 4-styrene sulfonate) (PSS) via layer-by-layer deposition. The polyelectrolyte (PE) adsorption processes are monitored real-time by optical reflectometry and a quartz crystal microbalance with dissipation monitoring (QCM-D). Compared to the reference PSS/PAH PEMs, the PSS/PAH-Gu PEMs show a lower amount of deposited PE materials, lower wet thickness, higher stability under alkaline conditions and higher rigidity. These differences are rationalized by the additional Gu-SO3 - interactions, also affecting the conformation of the PE chains in the PEM. The interactions between the PEMs and various sodium salts (NaCl, NaNO3, Na2SO4 and NaH2PO4) are also monitored using QCM-D. From the changes in the frequency, dissipation responses and supportive Reflection Absorption Infrared Spectroscopy it is concluded that Gu-functionalized PEMs absorb more H2PO4 - compared to the Gu-free reference PEMs. This can be understood by strong interactions between Gu and H2PO4 -, the differences in the anion hydration energy and the anion valency. It is anticipated that compounds like the presented Gu-functionalized PE may facilitate the further development of H2PO4 - sensors and ion separation/recovery systems.