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Microcantilevers modified with a self-assembled monolayer respond sensitively to specific ion concentrations. Here, we report the detection of trace amounts of CrO4(2-) using microcantilevers modified with a self-assembled monolayer of triethyl-12-mercaptododecylammonium bromide. The self-assembled monolayer was prepared on a silicon microcantilever coated with a thin layer of gold on one side. The microcantilever undergoes bending due to sorption of CrO4(2-) ions on the monolayer-modified side. It was found that a concentration of 10(-9) M CrO4(2-) can be detected using this technology in a flow cell. Other anions, such as Cl-, Br-, CO3(2-) (or HCO3-), and SO4(2-), have minimal effect on the deflection of this cantilever. The mechanics of the bending and the chemistry of cantilever modification are discussed.

Laser vaporization (LV) is a remarkably versatile technique for the catalytically-aided synthesis of nanomaterials, such as single-wall carbon nanotubes (SWNT). SWNT show remarkable promise for future generations of electronics and structural materials, however their application and commercialization has been hampered by a lack of control over the synthesis process, and low production quantities. Time-resolved in situ spectroscopic investigations of the laser-vaporization SWNT-synthesis process are described which are yielding some of the first direction determinations of carbon nanotube growth mechanisms and rates necessary to evaluate strategies for controllable synthesis and large-scale production. Our measurements indicate that SWNT grow over extended annealing times during the LV process by the conversion of condensed phase nanoparticle feedstock. These measurements were extended to grow carbon nanotubes by CO2- laser-annealing heat treatments of carbon and metal nanoparticle mixtures, offering an alternative synthesis approach to vapor- phase methods. These results present opportunities for scaled-up production of nanomaterials compatible with commercial high- power-laser technology.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Laser vaporization (LV) is a remarkably versatile technique for the catalytically-aided synthesis of nanomaterials, such as single-wall carbon nanotubes (SWNT). SWNT show remarkable promise for future generations of electronics and structural materials, however their application and commercialization has been hampered by a lack of control over the synthesis process, and low production quantities. Time-resolved in situ spectroscopic investigations of the laser-vaporization SWNT-synthesis process are described which are yielding some of the first direct determinations of carbon nanotube growth mechanisms and rates necessary to evaluate strategies for controllable synthesis and large-scale production. Our measurements indicate that SWNT grow over extended annealing times during the LV process by the conversion of condensed phase nanoparticulate feedstock. These measurements were extended to grow carbon nanotubes by CO2-laser-annealing heat treatments of carbon and metal nanoparticle mixtures, offering an alternative synthesis approach to vapor-phase methods. These results present opportunities for scaled-up production of nanomaterials compatible with commercial high-power laser technology.Laser vaporization (LV) is a remarkably versatile technique for the catalytically-aided synthesis of nanomaterials, such as single-wall carbon nanotubes (SWNT). SWNT show remarkable promise for future generations of electronics and structural materials, however their application and commercialization has been hampered by a lack of control over the synthesis process, and low production quantities. Time-resolved in situ spectroscopic investigations of the laser-vaporization SWNT-synthesis process are described which are yielding some of the first direct determinations of carbon nanotube growth mechanisms and rates necessary to evaluate strategies for controllable synthesis and large-scale production. Our measurements indicate that SWNT grow over extended annealing times during the LV process by the conversion of condensed phase nanoparticulate feedstock. These measurements were extended to grow carbon nanotubes by CO2-laser-annealing heat treatments of carbon and metal nanoparticle mixtures, offering an alt...

The accurate measurement of the molecular weight of deoxyribonucleic acid (DNA) oligomers is of great importance inmany disciplines ranging from molecular biology and medical diagnostics to agriculture and forensic sciences. Widely-used assays encode biological information, such as the presence of a normal or altered gene, identity of a criminal or

Well-defined acryloyl beta-alanine (ABA) polymers were synthesized directly via atom transfer radical polymerization (ATRP) under near physiological conditions using various water soluble initiators with high yield and narrow molecular weight distributions.