9 research outputs found
Feasibility of Carbon Nanoparticle Coatings as Protective Barriers for CopperWetting Assessment
Copper is extensively used in a wide
range of industrial
and daily-life
applications, varying from heat exchangers to electrical wiring. Although
it is protected from oxidation by its native oxide layer, when subjected
to harsh environmental conditionssuch as in coastal regionsthis
metal can rapidly degrade. Therefore, in this study, we analyze the
potential use of carbon nanoparticle coatings as protective barriers
due to their intrinsic hydrophobic wetting behavior. The nanocarbon
coatings were produced via electrophoretic deposition on Cu platelets
and characterized via scanning electron microscopy, confocal laser
scanning microscopy, and sessile drop test; the latter being the primary
focus since it provides insights into the wetting behavior of the
produced coatings. Among the measured coatings, graphite flakes, graphene
oxide, and carbon nanotube (CNT) coatings showed superhydrophobic
behavior. Based on their wetting behavior, and specifically for electrical
applications, CNT coatings showed the most promising results since
these coatings do not significantly impact the substrate’s
electrical conductivity. Although CNT agglomerates do not affect the
wetting behavior of the attained coatings, the coating’s thickness
plays an important role. Therefore, to completely coat the substrate,
the CNT coating should be sufficiently thickabove approximately
1 μm
Feasibility of Carbon Nanoparticle Coatings as Protective Barriers for CopperWetting Assessment
Copper is extensively used in a wide
range of industrial
and daily-life
applications, varying from heat exchangers to electrical wiring. Although
it is protected from oxidation by its native oxide layer, when subjected
to harsh environmental conditionssuch as in coastal regionsthis
metal can rapidly degrade. Therefore, in this study, we analyze the
potential use of carbon nanoparticle coatings as protective barriers
due to their intrinsic hydrophobic wetting behavior. The nanocarbon
coatings were produced via electrophoretic deposition on Cu platelets
and characterized via scanning electron microscopy, confocal laser
scanning microscopy, and sessile drop test; the latter being the primary
focus since it provides insights into the wetting behavior of the
produced coatings. Among the measured coatings, graphite flakes, graphene
oxide, and carbon nanotube (CNT) coatings showed superhydrophobic
behavior. Based on their wetting behavior, and specifically for electrical
applications, CNT coatings showed the most promising results since
these coatings do not significantly impact the substrate’s
electrical conductivity. Although CNT agglomerates do not affect the
wetting behavior of the attained coatings, the coating’s thickness
plays an important role. Therefore, to completely coat the substrate,
the CNT coating should be sufficiently thickabove approximately
1 μm
Feasibility of Carbon Nanoparticle Coatings as Protective Barriers for CopperWetting Assessment
Copper is extensively used in a wide
range of industrial
and daily-life
applications, varying from heat exchangers to electrical wiring. Although
it is protected from oxidation by its native oxide layer, when subjected
to harsh environmental conditionssuch as in coastal regionsthis
metal can rapidly degrade. Therefore, in this study, we analyze the
potential use of carbon nanoparticle coatings as protective barriers
due to their intrinsic hydrophobic wetting behavior. The nanocarbon
coatings were produced via electrophoretic deposition on Cu platelets
and characterized via scanning electron microscopy, confocal laser
scanning microscopy, and sessile drop test; the latter being the primary
focus since it provides insights into the wetting behavior of the
produced coatings. Among the measured coatings, graphite flakes, graphene
oxide, and carbon nanotube (CNT) coatings showed superhydrophobic
behavior. Based on their wetting behavior, and specifically for electrical
applications, CNT coatings showed the most promising results since
these coatings do not significantly impact the substrate’s
electrical conductivity. Although CNT agglomerates do not affect the
wetting behavior of the attained coatings, the coating’s thickness
plays an important role. Therefore, to completely coat the substrate,
the CNT coating should be sufficiently thickabove approximately
1 μm
Feasibility of Carbon Nanoparticle Coatings as Protective Barriers for CopperWetting Assessment
Copper is extensively used in a wide
range of industrial
and daily-life
applications, varying from heat exchangers to electrical wiring. Although
it is protected from oxidation by its native oxide layer, when subjected
to harsh environmental conditionssuch as in coastal regionsthis
metal can rapidly degrade. Therefore, in this study, we analyze the
potential use of carbon nanoparticle coatings as protective barriers
due to their intrinsic hydrophobic wetting behavior. The nanocarbon
coatings were produced via electrophoretic deposition on Cu platelets
and characterized via scanning electron microscopy, confocal laser
scanning microscopy, and sessile drop test; the latter being the primary
focus since it provides insights into the wetting behavior of the
produced coatings. Among the measured coatings, graphite flakes, graphene
oxide, and carbon nanotube (CNT) coatings showed superhydrophobic
behavior. Based on their wetting behavior, and specifically for electrical
applications, CNT coatings showed the most promising results since
these coatings do not significantly impact the substrate’s
electrical conductivity. Although CNT agglomerates do not affect the
wetting behavior of the attained coatings, the coating’s thickness
plays an important role. Therefore, to completely coat the substrate,
the CNT coating should be sufficiently thickabove approximately
1 μm
Feasibility of Carbon Nanoparticle Coatings as Protective Barriers for CopperWetting Assessment
Copper is extensively used in a wide
range of industrial
and daily-life
applications, varying from heat exchangers to electrical wiring. Although
it is protected from oxidation by its native oxide layer, when subjected
to harsh environmental conditionssuch as in coastal regionsthis
metal can rapidly degrade. Therefore, in this study, we analyze the
potential use of carbon nanoparticle coatings as protective barriers
due to their intrinsic hydrophobic wetting behavior. The nanocarbon
coatings were produced via electrophoretic deposition on Cu platelets
and characterized via scanning electron microscopy, confocal laser
scanning microscopy, and sessile drop test; the latter being the primary
focus since it provides insights into the wetting behavior of the
produced coatings. Among the measured coatings, graphite flakes, graphene
oxide, and carbon nanotube (CNT) coatings showed superhydrophobic
behavior. Based on their wetting behavior, and specifically for electrical
applications, CNT coatings showed the most promising results since
these coatings do not significantly impact the substrate’s
electrical conductivity. Although CNT agglomerates do not affect the
wetting behavior of the attained coatings, the coating’s thickness
plays an important role. Therefore, to completely coat the substrate,
the CNT coating should be sufficiently thickabove approximately
1 μm
Local Structure-Driven Localized Surface Plasmon Absorption and Enhanced Photoluminescence in ZnO-Au Thin Films
Nanocomposite
films consisting of gold nanoparticles embedded in
zinc oxide (ZnO-Au) have been synthesized with different gold loadings
by reactive magnetron sputtering at near-room temperature followed
by ex situ annealing in air up to 300 °C. Using X-ray diffraction
and high resolution transmission microscopy it is shown that during
deposition gold substitutes zinc in ZnO as isolated atoms and in nanoparticles
still exhibiting the structure of ZnO. Both situations degrade the
crystalline quality of the ZnO matrix, but thermal annealing cures
it from isolated gold atoms and triggers the formation of gold nanoparticles
of size higher than 3 nm, sufficient to observe a strong activation
of localized surface plasmon resonance (LSPR). The amplitude of LSPR
absorption observed after annealing increases with the gold loading
and annealing temperature. Moreover, UV and visible photoluminescence
from the ZnO matrix is strongly enhanced upon activation of LSPR showing
strong coupling with the gold nanoparticles. Finally, modeling of
spectroscopic ellipsometry measurements unambiguously reveals how
curing the defects increases the optical bandgap of the ZnO matrix
and modifies the optical dielectric functions of the nanocomposite
and ZnO matrix
Deterministic Coupling of a Single Silicon-Vacancy Color Center to a Photonic Crystal Cavity in Diamond
Deterministic coupling of single
solid-state emitters to nanocavities
is the key for integrated quantum information devices. We here fabricate
a photonic crystal cavity around a preselected single silicon-vacancy
color center in diamond and demonstrate modification of the emitters
internal population dynamics and radiative quantum efficiency. The
controlled, room-temperature cavity coupling gives rise to a resonant
Purcell enhancement of the zero-phonon transition by a factor of 19,
coming along with a 2.5-fold reduction of the emitter’s lifetime
Surface Modification of Brass via Ultrashort Pulsed Direct Laser Interference Patterning and Its Effect on Bacteria-Substrate Interaction
In recent decades, antibiotic resistance has become a
crucial challenge
for human health. One potential solution to this problem is the use
of antibacterial surfaces, i.e., copper and copper alloys. This study
investigates the antibacterial properties of brass that underwent
topographic surface functionalization via ultrashort pulsed direct
laser interference patterning. Periodic line-like patterns in the
scale range of single bacterial cells were created on brass with a
37% zinc content to enhance the contact area for rod-shaped Escherichia coli (E. coli). Although the topography facilitates attachment of bacteria to
the surface, reduced killing rates for E. coli are
observed. In parallel, a high-resolution methodical approach was employed
to explore the impact of laser-induced topographical and chemical
modifications on the antibacterial properties. The findings reveal
the underlying role of the chemical modification concerning the antimicrobial
efficiency of the Cu-based alloy within the superficial layers of
a few hundred nanometers. Overall, this study provides valuable insight
into the effect of alloy composition on targeted laser processing
for antimicrobial Cu-surfaces, which facilitates the thorough development
and optimization of the process concerning antimicrobial applications
Local Modification of the Microstructure and Electrical Properties of Multifunctional Au–YSZ Nanocomposite Thin Films by Laser Interference Patterning
Nanocomposite films consisting of
gold nanoparticles embedded in
an yttria-stabilized zirconia matrix (Au–YSZ) have been synthesized
with different gold loadings by reactive magnetron sputtering followed
by ex situ annealing in air or laser interference patterning (LIP)
treatment. It is shown that the electrical conductivity of the nanocomposite
films can be modified to a large extent by changing the gold loading,
by thermal annealing, or by LIP. The structural and microstructural
analyses evidenced the segregation of metallic gold in crystalline
form for all synthesis conditions and treatments applied. Thermal
annealing above 400 °C is observed to trigger the growth of pre-existing
nanoparticles in the volume of the films. Moreover, pronounced segregation
of gold to the film surface is observed for Au/(Au + Zr + Y) ratios
above 0.40, which may prevent the use of thermal annealing to functionalize
gold-rich Au–YSZ coatings. In contrast, significant modifications
of the microstructure were detected within the interference spot (spot
size close to 2 × 2 mm) of LIP treatments only for the regions
corresponding to constructive interference. As a consequence, besides
its already demonstrated ability to modify the friction behavior of
Au–YSZ films, the LIP treatment enables local tailoring of
their electrical resistivity. The combination of these characteristics
can be of great interest for sliding electrical contacts