<div class="csl-bib-body">
<div class="csl-entry">Hackl, T., Schitter, G., & Mesquida, P. (2022). AC Kelvin Probe Force Microscopy Enables Charge Mapping in Water. <i>ACS Nano</i>. https://doi.org/10.1021/acsnano.2c07121</div>
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dc.identifier.issn
1936-0851
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/101850
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dc.description.abstract
Mapping charged chemical groups at the solid-liquid interface is important in many areas, ranging from colloidal systems to biomolecular interactions. However, classical methods to measure surface charges either lack spatial resolution or─like Kelvin-probe force microscopy (KPFM)─cannot be applied in aqueous solutions because a DC bias voltage is used. Here, we show that using AC Kelvin probe force microscopy (AC-KPFM), in which the DC bias is replaced with an AC voltage of sufficiently high frequency, the surface potential of spatially fixated, charged surface groups can be mapped in aqueous solution. We demonstrate this with micropatterned, functionalized alkanethiol layers which expose ionized amino- and carboxy-groups. These groups are representative of the charged groups of most biomolecules such as proteins. By adjusting the pH of the solution, the charge of the groups was reversibly altered, demonstrating the electrostatic nature of the measured signal. The influence of the electric double layer (EDL) on the measurement is discussed, and we, furthermore, show how charged, micropatterned layers can be used to spatially direct the deposition of nanoparticles of opposite charge.
en
dc.description.sponsorship
Fonds zur Förderung der wissenschaftlichen Forschung (FWF)
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dc.language.iso
en
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dc.publisher
American Chemical Society
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dc.relation.ispartof
ACS Nano
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dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
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dc.subject
AC-KPFM
en
dc.subject
atomic force microscopy
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dc.subject
microcontact printing
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dc.subject
self-assembled monolayer
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dc.subject
solid−liquid interface
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dc.subject
surface charge
en
dc.title
AC Kelvin Probe Force Microscopy Enables Charge Mapping in Water