Hall Measurements on Carbon Nanotube Paper Modified With Electroless Deposited Platinum

Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt) distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed

Plasmafeinreinigen. Perspektiven

The present article provides a survey of the use of low-pressure plasma plants for cleaning and the pretreatment of solvent and aqueous-alkaline processes, where even anorganic pollutions may be partly eliminated as well. Frequently, however, a wet chemical cleaning is still indispensable

Deposition of SiOx films from O2/HMDSO plasmas

The variation of O2/HMDSO ratio in an r.f. plasma was carried out to optimize SiOx film properties and deposition rates for the coating of polymers. A ratio exceeding 6:1 yields scratch resistant, quartz-like films with low carbon contents. The chemical composition was analyzed to SiO1.8C0.3 by XPS. A compact plasma reactor was developed generating homogeneous plasmas and depositions over large areas (up to 380×290 mm2). Furthermore, the total coverage of three-dimensional formed parts was managed with good adhesion of SiOx films to polymers like PC and PBT to reduce wear

Plasma functionalization of multiwalled carbon nanotube bucky papers and the effect on properties of melt-mixed composites with polycarbonate

Multiwalled carbon nanotubes in the form of bucky papers were modified using Ar/O-2 plasma and thereafter melt-mixed into polycarbonate. The effect of plasma modification on the nanotubes was followed by XPS, indicating the formation of carboxylic or ester groups at the nanotube surfaces. In the melt-mixed nanocomposites, the modified nanotubes exhibited a better macrodispersion and better phase adhesion to the matrix as evidenced by morphological investigations. The electrical percolation threshold was not altered and occurred below 0.5wt.-% nanotubes. The mechanical properties were improved by having higher values of stress at yield, stress till beyond the yield point, and strain at break illustrating the effect of both better dispersion and enhanced phase adhesion