Quantification of Fluorine Density in the Outermost Atomic Layer

Grampel, R.D. van de; Ming, Weihua; Gildenpfennig, A.; Lavèn, Jozua; Brongersma, Hidde H.; Linde, R. van der

doi:10.1021/la0353071

Cited by 30 publications

(27 citation statements)

References 34 publications

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“…Advancing water contact angles of MHDA-and PFDT-functionalized gold surfaces were found to be 748 6 38 and 1098 6 38, respectively. These are generally consistent with published values (van de Grampel et al, 2004;Wang et al, 2004), confirming that MHDA monolayers are hydrophilic and PFDT ones are hydrophobic. This difference in hydrophilicity permits selective adsorption of polymers and biomaterials through the methodology of patterning a gold surface with MHDA and ''backfilling'' the bare gold regions with PFDT.…”

Section: Resultssupporting

confidence: 92%

Template‐directed patterning of polymers and biomaterials

Chandekar

Sengupta

Whitten

2007

Microscopy Res & Technique

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A novel method of patterning surfaces with synthetic or biological polymers is demonstrated. It consists of using microcontact printing to pattern a gold surface with an adsorbate that imparts hydrophilicity; the remainder of the surface is covered with one that imparts hydrophobicity. 16-Mercaptohexadecanoic acid (MHDA) and 1H,1H,2H,2H-perfluorodecanethiol, respectively, have been used as the hydrophilic and hydrophobic adsorbates. This functionalized gold surface then serves as a template for patterning hydrophilic polymers and biomaterials, which are either spin-coated or drop-cast onto the surface. Using this methodology, it is shown by atomic force microscopy, scanning electron microscopy (SEM), and fluorescence microscopy that micron-scale patterns of a poly(ethylene)-block-poly(ethylene oxide) copolymer, poly-L-tryptophan, and bovine collagen can be fabricated, with these mimicking the MHDA patterns. For the block copolymer, it is found by atomic force microscopy that the heights of the polymer patterns decrease as their widths decrease. This is believed to be due to the inherent instability of tall, narrow polymer structures and the tendency of the polymer to minimize its exposed surface area. For poly-L-tryptophan, two different molecular weights of this polyamino acid have been studied, and different morphologies within the patterned regions are observed. While oligomeric poly-L-tryptophan (1,000-5,000 g/mol) gives smooth MHDA-covered patterns, the higher molecular weight (15,000-50,000 g/mol) yields fibrous ones.

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Section: Resultssupporting

confidence: 92%

Template‐directed patterning of polymers and biomaterials

Chandekar

Sengupta

Whitten

2007

Microscopy Res & Technique

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“…The very large CAH is likely due to the fact that the fluorinated chain (e.g., C 8 F 17 ) is not long enough to prevent the surface reorganization (i.e., to shield the polar urethane group from the interrogating liquid) upon contact with water during the CA measurements:18 when the water droplet is in contact with the film surface, the urethane group that originally sits below the top fluoroalkyl layer would have the opportunity to interact with water, leading to a low θ R . We examined the top atomic layer of the fluorinated PU surface containing 1 wt.‐% of fluorine by low energy ion scattering,19,20 and found only fluorine and carbon atoms are present, suggesting that oxygen and nitrogen atoms are primarily located beneath the top atomic layer.…”

Section: Introductionmentioning

confidence: 99%

The Discovery of Compounds That Stimulate the Activity of Kallikrein‐Related Peptidase 3 (KLK3)

et al. 2011

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Kallikrein-related peptidase 3 (KLK3), also known as prostate-specific antigen (PSA), is the most useful biomarker for prostate cancer (PCa). KLK3 is suggested to play a role in regulating cancer growth through anti-angiogenic activity in vivo and in vitro. This feature, together with its specificity for prostate tissue, makes KLK3 an intriguing target for the design of new therapies for PCa. 3D pharmacophores for KLK3-stimulating compounds were generated based on peptides that bind specifically to KLK3 and increase its enzymatic activity. As a result of pharmacophore-based virtual screening, four small, drug-like compounds with affinity for KLK3 were discovered and validated by capillary differential scanning calorimetry. One of the compounds also stimulated the activity of KLK3, and is therefore the first published small molecule with such an activity.

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“…42 As it was observed by XPS, the surface of the film annealed at 600°C is free from fluorine and a reduction of the surface wettability for the higher annealing temperatures should be expected since it is known that the fluorine surface concentration controls the surface energy. 43 However, the Raman results suggest the formation of larger graphitic domains for annealing temperatures higher than 300°C, and so, a more hydrophobic sur-face. In this way, the measured contact angles reflect the competition between these two opposite trends and only a slight increase was observed.…”

Section: Resultsmentioning

confidence: 95%

Effects of thermal annealing on the structural, mechanical, and tribological properties of hard fluorinated carbon films deposited by plasma enhanced chemical vapor deposition

Costa

Baumvol

Radke

et al. 2004

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Hard amorphous fluorinated carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition were annealed in vacuum for 30 min in the temperature range of 200-600°C. The structural and compositional modifications were followed by several analytical techniques: Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERDA), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Nanoidentation measurements and lateral force microscopy experiments were carried out in order to provide the film hardness and the friction coefficient, respectively. The internal stress and contact angle were also measured. RBS, ERDA, and XPS results indicate that both fluorine and hydrogen losses occur for annealing temperatures higher than 300°C. Raman spectroscopy shows a progressive graphitization upon annealing, while the surface became slightly more hydrophobic as revealed by the increase of the contact angle. Following the surface wettability reduction, a decrease of the friction coefficient was observed. These results highlight the influence of the capillary condensation on the nanoscale friction. The film hardness and the internal stress are constant up to 300°C and decrease for higher annealing temperatures, showing a direct correlation with the atomic density of the films. Since the thickness variation is negligible, the mass loss upon thermal treatment results in amorphous structures with a lower degree of cross-linking, explaining the deterioration of the mechanical properties of the a-C:F films.

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Quantification of Fluorine Density in the Outermost Atomic Layer

Cited by 30 publications

References 34 publications

Template‐directed patterning of polymers and biomaterials

Template‐directed patterning of polymers and biomaterials

The Discovery of Compounds That Stimulate the Activity of Kallikrein‐Related Peptidase 3 (KLK3)

Effects of thermal annealing on the structural, mechanical, and tribological properties of hard fluorinated carbon films deposited by plasma enhanced chemical vapor deposition

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