Adsorption of Gaseous Propylamine on Films of Polypyrrole in Different Oxidation States

1999 ◽  
Vol 64 (1) ◽  
pp. 1-12
Author(s):  
Vítězslav Papež ◽  
Šárka Brodská ◽  
Jan Langmaier ◽  
Zdeněk Samec ◽  
Karin Potje-Kamloth
Keyword(s):  
Work Function ◽  
Gas Phase ◽  
Quartz Crystal ◽  
Co Adsorption ◽  
Polymer Surface ◽  
Water Layer ◽  
Acetonitrile Solution ◽  
Water Vapour Pressure ◽  
Kelvin Probe ◽  
Adsorption Of Water

Quartz crystal microbalance and Kelvin probe were used to investigate the interaction between propylamine (PrNH2) vapour and polypyrrole (PPy) films. The films were prepared by oxidative electropolymerization of pyrrole on a platinum electrode in acetonitrile solution. The nature of interaction is strongly influenced by the oxidation state of the film and co-adsorption of water. On the surface of the oxidized PPy, water adsorbs to form a multilayer. The work function increase of the Pt/PPy electrode exposed to both water and PrNH2 vapoures was attributed to the PrNH2 dissolution and dissociation within the water layer followed by the formatted PrNH3+ cation adsorption on the liquid surface with the alkyl group facing the gas phase. On the contrary, the water adsorption on the reduced PPy is rather weak and the work function decrease observed at the PrNH2 exposure might be connected with the neutral molecules adsorption directly on the polymer surface. The water co-adsorption is documented by a drop in the adsorption of PrNH2 upon lowering the water vapour pressure in the gas phase.

EFFECT OF GRAIN SIZE ON THE ELECTRON WORK FUNCTION OF Cu AND Al

2004 ◽  
Vol 11 (02) ◽  
pp. 173-178 ◽  
Author(s):  
WEN LI ◽  
D. Y. LI
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Grain Boundary ◽  
Work Function ◽  
Electron Work Function ◽  
Deformation Texture ◽  
Kelvin Probe ◽  
Surface Conditions ◽  
The Mean ◽  
Sophisticated Instrument

The Kelvin probe is a sophisticated instrument which is very sensitive to changes in surface conditions, such as deformation, texture, phase transformation and contamination. Efforts have been made to use this technique to diagnose wear. In this study, the effect of the grain boundary (GB) on the electron work function (EWF) was examined with the aim of investigating the contribution of changes in grain size to total changes in the EWF during wear. Copper and aluminum were studied as examples. It was demonstrated that the EWF dropped in the vicinity of GB's and the mean EWF decreased as the grain size decreased. The mechanism responsible for the changes in the EWF with respect to the GB is discussed.

scholarly journals Work function difference of naphthyl end-capped oligothiophene in different crystal alignments studied by Kelvin probe force microscopy

2020 ◽  
pp. 106060
Author(s):  
Mads Nibe Larsen ◽  
Mads Svanborg Peters ◽  
Rodrigo Lemos-Silva ◽  
Demetrio A. Da Silva Filho ◽  
Bjarke Jørgensen ◽  
...  
Keyword(s):  
Work Function ◽  
Kelvin Probe Force Microscopy ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Work Function Difference ◽  
Function Difference

Work Function on Dye-Adsorbed TiO2Surfaces Measured by Using a Kelvin Probe Force Microscope

2008 ◽  
Vol 112 (17) ◽  
pp. 6961-6967 ◽  
Author(s):  
Masatoshi Ikeda ◽  
Naoki Koide ◽  
Liyuan Han ◽  
Akira Sasahara ◽  
Hiroshi Onishi
Keyword(s):  
Work Function ◽  
Kelvin Probe

Co-adsorption of water and glycine on Cu{110}

2014 ◽  
Vol 16 (13) ◽  
pp. 6101 ◽  
Author(s):  
Marco Sacchi ◽  
Stephen J. Jenkins
Keyword(s):  
Co Adsorption ◽  
Adsorption Of Water

FORMATION OF SURFACE DIPOLES FOR SMALL PALLADIUM CLUSTERS DEPOSITED ON α-(0001)Al2O3

1996 ◽  
Vol 03 (01) ◽  
pp. 973-977 ◽  
Author(s):  
S. OGAWA ◽  
S. ICHIKAWA
Keyword(s):  
Charge Transfer ◽  
Single Crystal ◽  
Work Function ◽  
Probe Method ◽  
Kelvin Probe ◽  
Electronic Interactions ◽  
Palladium Clusters ◽  
Metal Support ◽  
Pd Clusters ◽  
Kelvin Probe Method

The Kelvin-probe method is utilized to measure the work function of a single-crystal aluminum covered with palladium clusters. It is found that formation of interface dipoles occurs by charge transfer from Al 2 O 3 to Pd clusters, particularly for those less than 2 nm in diameter. These results provide valuable clue to the understanding of metal-support electronic interactions, which is important in catalysis.

scholarly journals Droplet clusters: nature-inspired biological reactors and aerosols

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190121 ◽  
Author(s):  
Alexander A. Fedorets ◽  
Edward Bormashenko ◽  
Leonid A. Dombrovsky ◽  
Michael Nosonovsky
Keyword(s):  
Polymer Surface ◽  
Water Layer ◽  
Breath Figures ◽  
Self Organized ◽  
Droplet Cluster ◽  
Active Research ◽  
Living Nature ◽  
And Migration ◽  
Hexagonally Ordered

Condensed microdroplets play a prominent role in living nature, participating in various phenomena, from water harvesting by plants and insects to microorganism migration in bioaerosols. Microdroplets may also form regular self-organized patterns, such as the hexagonally ordered breath figures on a solid surface or levitating monolayer droplet clusters over a locally heated water layer. While the breath figures have been studied since the nineteenth century, they have found a recent application in polymer surface micropatterning (e.g. for superhydrophobicity). Droplet clusters were discovered in 2004, and they are the subject of active research. Methods to control and stabilize droplet clusters make them suitable for the in situ analysis of bioaerosols. Studying life in bioaerosols is important for understanding microorganism origins and migration; however, direct observation with traditional methods has not been possible. We report preliminary results on direct in situ observation of microorganisms in droplet clusters. We also present a newly observed transition between the hexagonally ordered and chain-like states of a droplet cluster. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

Study of the reaction CaSO4.½H2O (β-hemihydrate) = CaSO4 (β-soluble anhydrite)+½H2O in the temperature range 20–100° C

1965 ◽  
Vol 34 (268) ◽  
pp. 327-345 ◽  
Author(s):  
J. D. C. McConnell
Keyword(s):  
Water Vapour ◽  
Vapour Pressure ◽  
Physical Adsorption ◽  
Linear Increase ◽  
Water Vapour Pressure ◽  
Hydration Reaction ◽  
Temperature Range ◽  
Dehydration Reactions ◽  
Adsorption Of Water ◽  
Hydration And Dehydration

SummaryA thermogravimetric vacuum microbalance has been used to study the reaction between β-soluble anhydrite and water vapour in the temperature range 20–100° C. Equilibrium water-vapour pressures for the hydration reaction in this temperature range were determined directly and have been compared with available data obtained by Kelly, Southard, and Anderson (1941) in the temperature range 80–120° C. The kinetics of the hydration and dehydration reactions have also been studied in a series of isothermal experiments with varying water-vapour pressure. These experiments indicate that in a vapour-pressure range close to the equilibrium value very low rates for both hydration and dehydration are observed. Outside this range of vapour pressures both hydration and dehydration rates increase suddenly and show an approximately linear increase with imposed water-vapour pressure.At low temperatures (25° C) the dehydration reaction has an associated activation energy of approximately 10 kcal mole−1. In the same temperature range additional, physical adsorption of water vapour by the specimen was noted.

Sign in / Sign up

Export Citation Format

Share Document