Concentrated colloidal dispersion of decanoic acid self-assembled monolayer protected CeO2 nanoparticles up to 77 wt% in nonpolar organic solvents

2013 ◽  
Vol 1503 ◽  
Author(s):  
Toshihiko Arita ◽  
Jungwoo Yoo ◽  
Yu Ueda ◽  
Tadafumi Adschiri
Keyword(s):  
Organic Solvents ◽  
Packing Density ◽  
Decanoic Acid ◽  
Colloidal Dispersion ◽  
Ceo2 Nanoparticles ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Nonpolar Organic

ABSTRACTSelf-assembled monolayers (SAMs) of decanoic acids were prepared on cerium oxide nanoparticles (NPs). The dispersion of the NPs was improved by increasing the packing density of decanoic acid SAM on the NPs. Highly concentrated ceria nanofluids more than 22 vol% (about 77 wt%) in cyclohexane and trans-decalin were achieved, according to the criterion to the packing density and chain length of the alkanoic acid of the SAM to disperse the ceria NPs in nonpolar organic solvents proposed previously. Temperature effect on the dispersion was also examined and it was turned out that the dispersion was strongly enhanced with activation of Brownian motion.

Laser Polishing of Cold Work Steel AISI D2 for Dry Metal Forming Tools: Surface Homogenization, Refinement and Preparation for Self-Assembled Monolayers

2018 ◽  
Vol 767 ◽  
pp. 69-76 ◽  
Author(s):  
Ingo Ross ◽  
André Temmler ◽  
Moritz Küpper ◽  
Stephan Prünte ◽  
Marco Teller ◽  
...  
Keyword(s):  
Cold Extrusion ◽  
Self Assembled Monolayers ◽  
Homogeneous Distribution ◽  
Self Assembled Monolayer ◽  
Pulsed Laser Radiation ◽  
Laser Polishing ◽  
Assembled Monolayers ◽  
Aisi D2 ◽  
Self Assembled ◽  
Forming Tools

Liquid lubrication guarantees high precision and surface quality of workpieces in industrial forming processes. In the case of aluminum cold extrusion, wear and cold welding due to direct contact of tool and workpiece are usually prevented by the extensive use of lubricants. Since the use of lubricants is economically and ecologically unfavorable, surface treatments of tools by, e.g. laser polishing and/or coatings are in the focus of current investigations to substitute these lubricants and establish so called “dry metal forming” processes. The material AISI D2, a ledeburitic 12% chromium steel which is known to have a significant amount of chromium carbide precipitations, is widely used in cold extrusion for forming tools. The large fraction of chromium carbide precipitations, however, hinder the formation of a dense self-assembled monolayer (SAM) that is necessary to avoid direct contact of reactive aluminum with surface oxides of the tool. Therefore, a homogeneous distribution of the chemical elements with a smaller fraction or no chromium carbides in the steel matrix, particularly in the tool surface, is aimed for. Using laser polishing, the surface layer is molten by continuous or pulsed laser radiation. Within the melt pool, the elementary distribution is homogenized as a result of thermal convection and diffusion processes, as well as a smoothed surface and a grain refinement are achieved. Consequently, the effects of the surface treatment by laser polishing on the area coverage of self-assembled monolayers are investigated. Thus, a combined surface treatment by laser polishing and functionalization with a dense self-assembled monolayer shall reduce overall adhesive wear. For this investigation, several specimens of conventional manufactured and powder metallurgical molten AISI D2 are laser polished using continuous or pulsed laser radiation or a combination of both. The resulting surfaces are investigated by microscopy and spectroscopic techniques to analyze the surface topography and the elemental distribution near to the surface. These results are compared to those of conventionally hand-polished specimens. Furthermore, the influence of the element homogenization and grain refinement on the area coverage of self-assembled monolayers is explored. First results show that laser polishing of AISI D2 is suitable to achieve a reduction of grain size and a more homogeneous distribution of chromium carbides within the surface layer.

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

Self-Assembled Monolayers of 12-Mercaptododecylphosphonic Acid on Titania Particles; Application to the Extraction of Heavy Metals

2004 ◽  
Vol 847 ◽  
Author(s):  
Sébastien Anthérieu ◽  
Florence Brodard-Séverac ◽  
Gilles Guerrero ◽  
P. Hubert Mutin
Keyword(s):  
Heavy Metals ◽  
Chemical Analysis ◽  
Phosphonic Acid ◽  
Metal Extraction ◽  
Self Assembled Monolayers ◽  
Extraction Ability ◽  
Self Assembled Monolayer ◽  
Inorganic Hybrid ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACTTitania particles (P25 DEGUSSA AG) were treated by a solution of 12-mercaptododecyl-phosphonic acid (MDPA) in toluene to obtain an organic-inorganic hybrid material with thiol functions at the surface. This material was characterized by chemical analysis, solid state 31P MAS NMR and FTIR spectroscopies, and XPS. Reaction of the phosphonic acid end of MDPA with the TiO2 surface led to the formation of a relatively dense and well-ordered self-assembled monolayer (SAM), with a density of about 3.9 SH functions per nm2. This material was tested for the extraction of mercury in water at pH 7, 9, and 11. Chemical analysis indicated no loss of SH functionality, even at pH 11. The best extraction results were obtained at pH 9 and 11, with a metal extraction ability between 85 and 90%.

Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio

2007 ◽  
Vol 121-123 ◽  
pp. 495-498 ◽  
Author(s):  
Jun Hyung Park ◽  
Buyng Su Park ◽  
Gu Huh ◽  
Seung Hyun Lee ◽  
Hyun Sook Lee ◽  
...  
Keyword(s):  
Colorimetric Detection ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Local Domain ◽  
Mixing Ratio ◽  
Tunneling Microscopy ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled

We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.

Comparison of Proliferation and Growth of Human Keratinocytes on Plasma CO-Polymers of Acrylic acid/1,7- Octadiene and Self Assembled Monolayers

1998 ◽  
Vol 544 ◽  
Author(s):  
D. B. Haddow ◽  
R. M. France ◽  
R. D. Short ◽  
S. Macneil ◽  
R. A. Dawson
Keyword(s):  
Cell Proliferation ◽  
Tissue Culture ◽  
Carboxylic Acid ◽  
Cell Attachment ◽  
Human Keratinocytes ◽  
Collagen I ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled

AbstractHuman keratinocytes have been cultured on plasma co-polymers (PCPs), self assembled monolayers (SAMs), tissue culture poly(styrene) (TCPS) and collagen I. The degree of keratinocyte attachment was measured over 24 hours and cell proliferation and growth monitored over 7 days using optical microscopy and DNA concentrations. Cell attachment and proliferation and growth on the PCP surfaces were compared with 2 self assembled monolayer (SAM) systems. PCP surfaces containing carboxylic acid functionalities promoted keratinocyte attachment, with optimum attachment levels seen on surfaces containing less than 5% acid groups. The level of attachment on these surfaces was comparable to that seen on collagen I, a preferred substratum for the culturing of keratinocytes. After several days in culture the cells were well attached and proliferative. Keratinocytes attached well to acidterminated SAMs but attached poorly to methyl-terminated SAMs.

Coating a DNA self-assembled monolayer with a metal organic framework-based exoskeleton for improved sensing performance

The Analyst ◽  
2019 ◽  
Vol 144 (11) ◽  
pp. 3539-3545 ◽  
Author(s):  
Jiehua Ma ◽  
Wenxin Chai ◽  
Jianyang Lu ◽  
Tian Tian ◽  
Shuai Wu ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
New Strategy ◽  
Assembled Monolayers ◽  
Metal Organic ◽  
Self Assembled ◽  
Poor Stability ◽  
Sensing Performance ◽  
Organic Framework

The relatively poor stability of DNA self-assembled monolayers (SAMs) greatly limits their use in real applications. A new strategy is reported to protect the DNA SAMs by using a metal organic framework (MOF)-based exoskeleton.

Packing density of HS(CH2)nCOOH self-assembled monolayers

The Analyst ◽  
2011 ◽  
Vol 136 (23) ◽  
pp. 4935 ◽  
Author(s):  
A. W. Snow ◽  
G. G. Jernigan ◽  
M. G. Ancona
Keyword(s):  
Packing Density ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled
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