Universität zu Köln

Renner, Alexander M., Schuetz, Markus B., Moog, Daniel, Fischer, Thomas and Mathur, Sanjay (2019). Electroacoustic Quantification of Surface Bound Ligands in Functionalized Silica and Iron Oxide Nanoparticles. ChemistrySelect, 4 (40). S. 11959 - 11965. WEINHEIM: WILEY-V C H VERLAG GMBH. ISSN 2365-6549

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Abstract

The electrokinetic sonic amplitude (ESA) is one of the most versatile techniques for deriving the zeta potential of nanoparticles before, during and after surface functionalization with different ligands, thus overcoming current limitations of well-established electrophoretic measurement principles. We present a novel method for direct quantification of accessible hydroxide groups available on the surface of silica nanoparticles by the ESA effect, supported by simultaneous electrical conductivity measurements. Moreover, the in-operando determination of varying zeta potential during addition of carboxylic acids demonstrate a profound way to quantify surface-bound ligands, which still poses a challenge in following the surface modification of nanoparticles. In this study, phase pure cuboidal hematite particles were chosen as a model system with an initial zeta potential between +50 and +55 mV in ethanol. Using both citric acid and 10-undecynoic acid as surface-modifiers, the correlation between the degree of surface functionalization and zeta potential was investigated. The decrease of zeta potential of hematite particles during the titration of 10-undecynoic acid or citric acid could be directly correlated to a successful surface functionalization in contrast to a surface protonation, which would be expected in case of both carboxylic acids. Furthermore, the addition of 10-undecynoic acid led to a stabilization effect on the zeta potential of cuboidal hematite particles. These results highlight the hitherto unexplored potential of ESA techniques as a quantification method in nanoparticle surface modification.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Renner, Alexander M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schuetz, Markus B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Moog, Daniel UNSPECIFIED UNSPECIFIED UNSPECIFIED Fischer, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Mathur, Sanjay UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-130341
DOI:	10.1002/slct.201902710
Journal or Publication Title:	ChemistrySelect
Volume:	4
Number:	40
Page Range:	S. 11959 - 11965
Date:	2019
Publisher:	WILEY-V C H VERLAG GMBH
Place of Publication:	WEINHEIM
ISSN:	2365-6549
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GOLD NANOPARTICLES; ZETA-POTENTIALS; SUSPENSIONS; DISPERSION; PARTICLES; STABILITY; RESONANCE; IMPROVE; ALUMINA; MONO Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13034