Optical Studies of Polyanilines: Effects of Alkyl Ring-Substitution and Solvent Environment

1989 ◽  
Vol 173 ◽  
Author(s):  
Anjan Ray ◽  
Alan G. MacDiarmid ◽  
John M. Ginder ◽  
Arthur J. Epstein
Keyword(s):  
Acetic Acid Solution ◽  
Exciton Absorption ◽  
Optical Studies ◽  
Band Formation ◽  
Near Ir ◽  
Alkyl Groups ◽  
Solvent Environment ◽  
Polaron Band ◽  
Uv Visible ◽  
Spectroscopy Optical

ABSTRACTMethyl and ethyl ring-substituted polyaniline derivatives have been synthesized and characterized by UV-visible-near IR spectroscopy. Optical spectra of the base forms in DMF solution suggest that the torsion angle between adjacent rings is increased by steric hindrance due to the alkyl groups in the substituted polymers, leading to blue shifts in the ∼4 eV (“bandgap”) and ∼2 eV (“exciton”) absorptions and an accompanying decrease in the relative intensity of the “exciton” band.The methyl ring-substituted derivative, poly(o-toluidine), is shown to exhibit solvatochromism. The “exciton” absorption shifts from 2.03 eV in pure NMP to 2.19 eV in CH2CI2, accompanied by a loss in intensity relative to the “exciton” absorption.The phenomenon is attributed to the presence of a more “rod-like” state in NMP as compared to a more “coil-like” state in CH2CI2.The effects of alkyl substituents on acetic acid solution spectra of “emeraldine” salt will be discussed with respect to polaron band formation in these systems.

scholarly journals Evaluation of N-Alkyl-bis-o-aminobenzamide Receptors for the Determination and Separation of Metal Ions by Fluorescence, UV-Visible Spectrometry and Zeta Potential

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1737 ◽  
Author(s):  
Marisela Martinez-Quiroz ◽  
Xiomara E. Aguilar-Martinez ◽  
Mercedes T. Oropeza-Guzman ◽  
Ricardo Valdez ◽  
Eduardo A. Lopez-Maldonado
Keyword(s):  
Aqueous Solution ◽  
Zeta Potential ◽  
Metal Ions ◽  
Environmental Concern ◽  
Separation Of Metal Ions ◽  
Complexing Capacity ◽  
Alkyl Groups ◽  
Molecular Fluorescence ◽  
Uv Visible ◽  
Phase Sensor

This paper presents the synthesis and evaluation of physicochemical behavior of a new series of N-alkyl-bis-o-aminobenzamides (BOABs) in aqueous solution. The study was targeted to the complexing capacity of five metal ions (Fe2+, Cu2+, Cd2+, Hg2+ and Pb2+) of environmental concern as the medullar principle of a liquid phase sensor for its application in the determination of these metal ions due to its versatility of use. Molecular fluorescence, UV-visible and Zeta potential were measured for five BOABs and the effect of alkyl groups with different central chain length (n = 3, 4, 6, 8 and 10) on physicochemical performance determined. The results have shown that these derivatives present higher sensibility and selectivity for Cu2+ even in the presence of the other metal ions. An additional application test was done adding a pectin (0.1 wt %) solution to the BOAB-Cu+2 complex to obtain a precipitate (flocs) as a potential selective separation process of Cu from aqueous solution. The solid was then lyophilized and analyzed by SEM-EDS, the images showed spheric forms containing Cu+2 with diameter of approximately of 8 μm and 30 wt %.

scholarly journals Autofluorescence spectroscopy and imaging: a tool for biomedical research and diagnosis

2014 ◽  
Author(s):  
A.C. Croce ◽  
G. Bottiroli
Keyword(s):  
Scientific Community ◽  
Data Interpretation ◽  
Near Ir ◽  
Endogenous Fluorophores ◽  
Biological Substrate ◽  
Autofluorescence Spectroscopy ◽  
Uv Visible ◽  
Biological Substrates ◽  
Relationship Of

Native fluorescence, or autofluorescence (AF), consists in the emission of light in the UV-visible, near-IR spectral range when biological substrates are excited with light at suitable wavelength. This is a well-known phenomenon, and the strict relationship of many endogenous fluorophores with morphofunctional properties of the living systems, influencing their AF emission features, offers an extremely powerful resource for directly monitoring the biological substrate condition. Starting from the last century, the technological progresses in microscopy and spectrofluorometry were convoying attention of the scientific community to this phenomenon. In the future, the interest in the autofluorescence will certainly continue. Current instrumentation and analytical procedures will likely be overcome by the unceasing progress in new devices for AF detection and data interpretation, while a progress is expected in the search and characterization of endogenous fluorophores and their roles as intrinsic biomarkers.

scholarly journals Near-Ir Resonance Raman and Uv-Visible Absorption Kinetic Spectroscopy of Optogenetic Archaerhodopsin Neuronal Silencers: Effects of Membrane Potential

2013 ◽  
Vol 104 (2) ◽  
pp. 680a
Author(s):  
John I. Ogren ◽  
Erica C. Saint Clair ◽  
Sergey Mamaev ◽  
Daniel Russano ◽  
Joel M. Kralj ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Resonance Raman ◽  
Visible Absorption ◽  
Kinetic Spectroscopy ◽  
Near Ir ◽  
Absorption Kinetic ◽  
Uv Visible

On the Radiation Stability of BaSO4 Pigment Modified with SiO2 Nanoparticles and Applied for Spacecraft Thermal Control Coatings

2018 ◽  
Vol 386 ◽  
pp. 277-282 ◽  
Author(s):  
Mikhail M. Mikhailov ◽  
Vitaly V. Neshchimenko ◽  
Semyon A. Yuryev ◽  
Anatoly V. Grigorevsky ◽  
Alexey A. Lovitskiy ◽  
...  
Keyword(s):  
Thermal Control ◽  
Radiation Stability ◽  
Maximum Effect ◽  
Nanoparticle Concentration ◽  
Absorption Bands ◽  
Near Ir ◽  
Uv Visible ◽  
Thermal Control Coatings ◽  
Spacecraft Thermal Control ◽  
High Temperature Modification

The authors investigated the effect of a high-temperature modification with SiO2 nanoparticles on the optical properties and radiation stability of BaSO4 powders. The modification leads to insignificant alteration in the reflecting capacity within the UV, visible, and near-IR spectral regions. Appending SiO2 nanoparticles with a concentration of up to 10 wt.% results in the increasing radiation stability of BaSO4 powders. The maximum effect was obtained due to the decreasing intensity of the absorption bands at 270-280, 375-395, 440-460, 500-600, 700, and 950 nm at a nanoparticle concentration of 3 wt.%.

scholarly journals Boosting the Seebeck Coefficient for Organic Coordination Polymers: Role of Doping-Induced Polaron Band Formation

2019 ◽  
Vol 10 (10) ◽  
pp. 2493-2499 ◽  
Author(s):  
Yunpeng Liu ◽  
Wen Shi ◽  
Tianqi Zhao ◽  
Dong Wang ◽  
Zhigang Shuai
Keyword(s):  
Seebeck Coefficient ◽  
Coordination Polymers ◽  
Band Formation ◽  
Polaron Band
Sign in / Sign up

Export Citation Format

Share Document