Search

Showing total 2 results
Start Over Topic chemical potential
2 results

1. Detection of CdSe Quantum Dot Photoluminescence for Security Label on Paper.

Author

Isnaeni, Sugiarto, Iyon Titok, Bilqis, Ratu, and Suseno, Jatmiko Endro

Subjects
*CADMIUM selenide, *CHEMICAL detectors, *QUANTUM dots, *PHOTOLUMINESCENCE, *PAPER, *CHEMICAL potential
Abstract

CdSe quantum dot has great potential in various applications especially for emitting devices. One example potential application of CdSe quantum dot is security label for anti-counterfeiting. In this work, we present a practical approach of security label on paper using one and two colors of colloidal CdSe quantum dot, which is used as stamping ink on various types of paper. Under ambient condition, quantum dot is almost invisible. The quantum dot security label can be revealed by detecting emission of quantum dot using photoluminescence and cnc machine. The recorded quantum dot emission intensity is then analyzed using home-made program to reveal quantum dot pattern stamp having the word 'RAHASIA'. We found that security label using quantum dot works well on several types of paper. The quantum dot patterns can survive several days and further treatment is required to protect the quantum dot. Oxidation of quantum dot that occurred during this experiment reduced the emission intensity of quantum dot patterns. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

2. Liquid Expanded Monolayers of Lipids As Model Systems to Understand the Anionic Hofmeister Series: 2. Ion Partitioning Is Mostly a Matter of Size

Author

Leontidis, Epameinondas, Aroti, Andria, and Leontidis, Epameinondas [0000-0003-4427-0398]

Subjects
Electrolyte solutions, Ionic bonding, Electrolyte, Negative ions, Phase interfaces, Electrolytes, Lipid dispersions, Ionic radius, Materials Chemistry, Metal ions, Lipid bilayer, Hydrophilicity, Chemistry, Ionic specificities, Chlorine compounds, Ion hydrations, Dynamics, Surfaces, Coatings and Films, Hydrophobic anions, Complex models, Ion partitioning, Ionic sizes, Chemicals, Sodium salts, Paper, Ion specificities, Hofmeister series, Lipid monolayers, Surface pressures, Sodium, Ionic volumes, Inorganic chemistry, chemistry.chemical_element, Molecular dynamics, Ion, Sodium ions, Model systems, Molecule, Lipid molecules, Physical and Theoretical Chemistry, Dipalmitoyl-phosphatidylcholine, Sodium fluorides, Lipid models, Monolayers, Head groups, Molecular dynamics simulations, Anionic hofmeister, Physical chemistry, Salts, Lipid layers, Ionization of liquids, Specific anion effects, B-coefficients, Chemical potential, Acetate ions
Abstract

In the preceding paper of this series [Leontidis, E. Aroti, A. Belloni, L. J. Phys. Chem. B 2009, 113, 1447], we considered and modeled the increase of the surface pressure of dipalmitoyl phosphatidylcholine (DPPC) monolayers over electrolyte solutions of various monovalent sodium salts. The experimental results for salts with large, less hydrophilic anions can be successfully described by models treating ionic specificity either as specific partitioning in the interfacial lipid layer or as a result of ion-lipid dispersion interactions. However, the results for salts with more hydrophilic anions, such as chloride and fluoride, cannot be fitted by any of these models, while they clearly demonstrate the existence of a specific sodium-DPPC interaction. In the present paper, we first prove that the experimental results for sodium fluoride (NaF) can be fitted by a model that is based on simultaneous complexation of sodium ions with up to three lipid molecules, as suggested by recent molecular dynamics simulations. We then return to the experimental results of sodium salts with more hydrophobic anions, treated in the preceding paper, and prove that these can be fitted equally well with a complex model, which accounts for both sodium complexation with the lipid head groups and anion partitioning within the lipid monolayers. The partitioning parameters obtained from this more complete model correlate well with several measures of ion specificity, such as ionic volume, von Hippel chromatographic parameters, or viscosity B-coefficients. A model for these partitioning chemical potentials is created based on the competition of cavity and ion hydration terms. The model leads to an excellent correlation of the partitioning chemical potentials with a function of the ionic radius, suggesting that specific anion effects on this lipid model system are mostly a matter of ionic size. Two notable exceptions from this correlation are thiocyanate and acetate ions, the charge distribution of which is not spherically symmetric, so that they are expected to have orientational-dependent interactions with the water-lipid interface. The implications of the present results on ion specificity in general are discussed. © 2009 American Chemical Society. 113 5 1460 1467 Cited By :43

Published
2009
Full Text
View/download PDF