33 research outputs found
Synergistic Formation of Radicals by Irradiation with Both Vacuum Ultraviolet and Atomic Hydrogen: A Real-Time In Situ Electron Spin Resonance Study
We report on the surface modification of polytetrafluoroethylene (PTFE) as an
example of soft- and bio-materials that occur under plasma discharge by
kinetics analysis of radical formation using in situ real-time electron spin
resonance (ESR) measurements. During irradiation with hydrogen plasma,
simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and
the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the
C-DB density were observed in real time, where the rate of density change was
accelerated during initial irradiation and then became constant over time. It
is noteworthy that C-DBs were formed synergistically by irradiation with both
vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR
technique is useful to elucidate synergistic roles during plasma surface
modification.Comment: 14 pages, 4 figure
Surface engineering and self-cleaning properties of the novel TiO2/PAA/PTFE ultrafiltration membranes
High-Resolution Epifluorescence and Time-of-Flight Secondary Ion Mass Spectrometry Chemical Imaging Comparisons of Single DNA Microarray Spots
DNA microarray assay performance is commonly compromised
by spot–spot
probe and signal variations as well as heterogeneity within printed
microspots. Accurate metrics for captured DNA target signal rely upon
uniform spot distribution of both probe and target DNA to yield reliable
hybridized signal. While often presumed, this is neither easily achieved
nor often proven experimentally. High-resolution imaging techniques
were used to determine spot heterogeneity in identical DNA array microspots
comprising varied ratios of unlabeled and dye-labeled DNA probes contact-printed
onto commercial arraying surfaces. Epifluorescence imaging data for
individual array microspots were correlated with time-of-flight secondary
ion mass spectrometry (TOF-SIMS) chemical state imaging of the same
spots. Epifluorescence imaging intensity distinguished varying DNA
density distributed both within a given spot and from spot to spot.
TOF-SIMS chemical analysis confirmed these heterogeneous printed DNA
distributions by tracking bound Cy3 dye, DNA base, and phosphate specific
ion fragments often correlating to fluorescence patterns within identical
spots. TOF-SIMS ion fragments originating from probe DNA and Cy3 dye
are enriched in microspot centers, correlating with high fluorescence
intensity regions. Both TOF-SIMS and epifluorescence support Marangoni
flow effects on spot drying, with high-density DNA–Cy3 located
in spot centers and nonhomogeneous DNA distribution within printed
spots. Microspot image dimensional analysis results for DNA droplet
spreading show differing DNA densities across printed spots. The study
directly supports different DNA probe chemical and spatial microenvironments
within spots that yield spot–spot signal variations known to
affect DNA target hybridization efficiencies and kinetics. These variations
critically affect probe–target duplex formation and DNA array
signal generation
Drastic Improvement in Adhesion Property of Polytetrafluoroethylene (PTFE) via Heat-Assisted Plasma Treatment Using a Heater
Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma
The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115°, but only the filamentary argon discharge induces higher WCAs. Finally, nanoparticles were deposited under the fluorinated layer to increase the surface roughness and therefore produce super-hydrophobic hybrid coatings characterized by the nonadherence of the water droplet at the surface.SCOPUS: ar.jinfo:eu-repo/semantics/publishe