8 research outputs found
Unusual Nature of Fingerprints and the Implications for Easy-to-Clean Coatings
Irrespective
of the technology, we now rely on touch to interact
with devices such as smart phones, tablet computers, and control panels.
As a result, touch screen technologies are frequently in contact with
body grease. Hence, surface deposition arises from localized inhomogeneous
finger-derived contaminants adhering to a surface, impairing the visual/optical
experience of the user. In this study, we examined the contamination
itself in order to understand its static and dynamic behavior with
respect to deposition and cleaning. A process for standardized deposition
of fingerprints was developed. Artificial sebum was used in this process
to enable reproducibility for quantitative analysis. Fingerprint contamination
was shown to be hygroscopic and to possess temperature- and shear-dependent
properties. These results have implications for the design of easily
cleanable surfaces
Unusual Nature of Fingerprints and the Implications for Easy-to-Clean Coatings
Irrespective
of the technology, we now rely on touch to interact
with devices such as smart phones, tablet computers, and control panels.
As a result, touch screen technologies are frequently in contact with
body grease. Hence, surface deposition arises from localized inhomogeneous
finger-derived contaminants adhering to a surface, impairing the visual/optical
experience of the user. In this study, we examined the contamination
itself in order to understand its static and dynamic behavior with
respect to deposition and cleaning. A process for standardized deposition
of fingerprints was developed. Artificial sebum was used in this process
to enable reproducibility for quantitative analysis. Fingerprint contamination
was shown to be hygroscopic and to possess temperature- and shear-dependent
properties. These results have implications for the design of easily
cleanable surfaces
Direct Electron Beam Writing of Silver-Based Nanostructures
Direct
writing utilizing a focused electron beam constitutes an interesting
alternative to resist-based techniques, as it allows for precise and
flexible growth onto any conductive substrate in a single-step process.
One important challenge, however, is the identification of appropriate
precursors which allow for deposition of the material of choice, e.g.,
for envisaged applications in nano-optics. In this regard the coinage
metal silver is of particular interest since it shows a relatively
high plasma frequency and, thus, excellent plasmonic properties in
the visible range. By utilizing the precursor compound AgO<sub>2</sub>Me<sub>2</sub>Bu, direct writing of silver-based nanostructures via
local electron beam induced deposition could be realized for the first
time. Interestingly, the silver deposition was strongly dependent
on electron dose; at low doses of 30 nC/Ī¼m<sup>2</sup> a dominant
formation of pure silver crystals was observed, while at higher electron
doses around 10<sup>4</sup> nC/Ī¼m<sup>2</sup> large carbon contents
were measured. A scheme for the enhanced silver deposition under low
electron fluxes by an electronic activation of precursor dissociation
below thermal CVD temperature is proposed and validated using material
characterization techniques. Finally, the knowledge gained was employed
to fabricate well-defined two-dimensional deposits with maximized
silver content approaching 75 at. %, which was achieved by proper
adjustment of the deposition parameters. The corresponding deposits
consist of plasmonically active silver crystallites and demonstrate
a pronounced Raman signal enhancement of the carbonaceous matrix