The Study of Photoreversibility, Photopolimerization and Photocleavage Properties of Polyurethane Coumarin by Means of Electronic Spectrometry and AFM Methods

2017 ◽  
Vol 68 (7) ◽  
pp. 1632-1635
Author(s):  
Silviu Gurlui ◽  
Emil Buruiana ◽  
Ioan Gabriel Sandu ◽  
Mitachi Strat
Keyword(s):  
Uv Irradiation ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Photon Excitation ◽  
Photochemical Properties ◽  
Film State

The spectroscopic and photochemical properties of polyurethane coumarin (PUC) in dimethyl sulf-oxide (DMSO), thetra hydro furan (THF), dimethyl formamide (DMF) and film state were investigated at room temperature under one photon excitation. The results show that under irradiation of l ] 310 nm photodimerization process are increased and under UV irradiation with l[ 260 nm, photocleavage of polymer have been evidenced, too.

Photophysical and Photochemical Properties of Polyurethane Coumarin Studied by Means of Electronic Spectra

2017 ◽  
Vol 68 (7) ◽  
pp. 1568-1572 ◽  
Author(s):  
Mitachi Strat ◽  
Emil Buruiana ◽  
Dan Dumitriu ◽  
Andrei Victor Sandu ◽  
Silviu Gurlui
Keyword(s):  
Uv Irradiation ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Dimethyl Formamide ◽  
Polar Solvents ◽  
Spectra Analysis ◽  
Photon Excitation ◽  
Exciting Beam ◽  
Photochemical Properties ◽  
Fluorescence Wavelength

The spectroscopic and photochemical properties of polyurethane coumarine (PUC) in dimethyl sulf-oxide (DMSO), thetra hydro furan (THF), dimethyl formamide (DMF) and film state were investigated at room temperature under one photon excitation. Photodimer products were formed via UV irradiation. Syn head-to-head and syn head-to-tail photodimers were formed under one-photon (broadband UV) irradiation in polar solvents. The spectral investigation of the photochemical products of PUC revealed efficient fluorescence emission in the spectral region 300�400 nm, attributed to the syn-head-to-tail dimers of PUC. The results show that under irradiation of l ] 310 nm photodimerization process are increased and under UV irradiation with l [ 260 nm, photocleavage degree have been evidenced, too. Fluorescence spectra analysis of PUC in polar and film-based solvents reveals another very important result. The 375nm fluorescence wavelength of the PUC (exciting beam 310 nm) is about 30 times more intense than the same maximum in THF and in DMF. This result indicates a new method to confirm that PUC film photodimerisation occurs especially at its surface.

Nanoaggregates and Selforganization Phenomena in Polyurethane Coumarine Film

2017 ◽  
Vol 54 (3) ◽  
pp. 589-592
Author(s):  
Silviu Gurlui ◽  
Ion Sandu ◽  
Nicanor Cimpoesu ◽  
Valentin Pohoata ◽  
Ioan Gabriel Sandu ◽  
...  
Keyword(s):  
Solid State ◽  
Polymer Films ◽  
Room Temperature ◽  
Ftir Analysis ◽  
Dimer Formation ◽  
Photon Excitation ◽  
Afm Analysis ◽  
Photochemical Properties

The spectroscopic and photochemical properties of polyurethane coumarine (PUC) in solid state were investigated at room temperature under once-photon excitation. One photon induced photocycloaddition of PUC was investigated and the AFM and spectroscopic FTIR analysis confirmed dimer formation. The AFM analysis shows that the fotodimerization process occurs at the surface of polymer films. The polyurethane coumarine film on CaF2 unirradiated and irradiated underline both the fotodimerization of the polymer films as well as the photoclevage of the polyurethane coumarin.

Room-Temperature Chemical Synthesis of C2

2019 ◽  
Author(s):  
Kazunori Miyamoto ◽  
Shodai Narita ◽  
Yui Masumoto ◽  
Takahiro Hashishin ◽  
Mutsumi Kimura ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Ground State ◽  
Room Temperature ◽  
Chemical Species ◽  
Quadruple Bond ◽  
Photon Excitation ◽  
Physical Energy ◽  
Theoretical Predictions ◽  
Carbon Arc ◽  
Inherent Nature

Diatomic carbon (C<sub>2</sub>) is historically an elusive chemical species. It has long been believed that the generation of C<sub>2 </sub>requires extremely high “physical” energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C<sub>2 </sub><i>in the ground state </i>is experimentally inaccessible. Here, we present the first “chemical” synthesis of C<sub>2 </sub>in a flask at <i>room temperature or below</i>, providing the first experimental evidence to support theoretical predictions that (1) C<sub>2 </sub>has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that (2) C<sub>2 </sub>serves as a molecular element in the formation of sp<sup>2</sup>-carbon allotropes such as graphite, carbon nanotubes and C<sub>60</sub>.

The synthesis of Cyclododecane-r-1,c-5,c-9-triamine and r-1,c-5,c-9-Tris(2,3-dimethoxybenzamido)cyclododecane

1975 ◽  
Vol 28 (3) ◽  
pp. 673 ◽  
Author(s):  
DJ Collins ◽  
C Lewis ◽  
JM Swan
Keyword(s):  
Aqueous Solution ◽  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Sodium Carbonate ◽  
Sodium Azide ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Hydrolysis Of

Treatment of cyclododecane-r-1,c-5,c-9-triyl tris(p-toluenesulphonate) with sodium azide in dimethyl-formamide at 100� for 6 h gave the corresponding cis,cis-triazide which upon hydrogenation or reduction with lithium aluminium hydride gave cyclododecane-r-1,c-5,c-9-triamine, isolated as the tris-salicylidene derivative. Acid hydrolysis of this, removal of the salicylaldehyde, and treatment of the aqueous solution with sodium carbonate and 2,3-dimethoxybenzoyl chloride gave r-1,c-5,c- 9-tris(2,3-dimethoxybenzamido)cyclododecane. ��� Treatment of (E,E,E)-cyclododeca-1,5,9-triene with an excess of acetonitrile and sulphuric acid at room temperature for three days gave 18% of (E,E)-1-acetamidocyclododeca-4,8-diene; no di- or tri-amides were isolated.

Manganese Oxide Photodeposited onto Titanium Dioxide as a New Environmental Catalyst

2005 ◽  
Vol 480-481 ◽  
pp. 117-122 ◽  
Author(s):  
Ayumu Tateoka ◽  
Yoshika Sekine ◽  
Takamasa Tsuda ◽  
Takanobu Ohashi
Keyword(s):  
Carbon Dioxide ◽  
Titanium Dioxide ◽  
Manganese Oxide ◽  
Organic Compounds ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Complex Oxide ◽  
Environmental Catalysis ◽  
Environmental Catalyst ◽  
Formaldehyde In Air

Authors have successfully synthesized a new environmental catalysis which reacted with harmful formaldehyde in air at room temperature. Although manganese oxide is practically used for a major ingredient of formaldehyde removing materials, intermediates such as formate formed on the surface reduced the removal efficiency. Then, manganese oxide was photodeposited onto the surface of titanium dioxide particles which could decompose certain organic compounds with UV irradiation. It was confirmed that the complex oxide decomposed formaldehyde into carbon dioxide at room temperature. Moreover, UV irradiation enhanced the production of the carbon dioxide.

Electronic Spectral Investigations upon the Photochemical Transformations of Some Substituted 1-(N,N-bisacyl)amino-4,5-diphenyl-l,2,3-triazoles

2001 ◽  
Vol 56 (6-7) ◽  
pp. 452-458
Author(s):  
Irina Petkova ◽  
Apostolos J. Maroulis ◽  
Constantina Hadjiantoniou-Maroulis ◽  
Peter Nikolov
Keyword(s):  
Steady State ◽  
Room Temperature ◽  
Uv Light ◽  
Uv Absorption ◽  
Luminescence Spectra ◽  
Model Compounds ◽  
Photochemical Transformations ◽  
Absorption And Luminescence Spectra ◽  
Photochemical Properties ◽  
Substituted 1

Abstract The objective of this report is to investigate the steady state and dynamic photophysical and photochemical properties of 1-(N,N-bisacyl)amino-4,5-diphenyl-1,2,3-triazoles in solvents of dif­ferent polarity at room temperature and in frozen matrix at 77 K. On the basis of the comparison of their UV absorption and luminescence spectra with those of 4,5-diphenyl-1,2,3-triazole and diben-zamide (model compounds), cleavage of the N-N bond in the title compounds after irradiation with polychrome UV light is proved.

scholarly journals Enhanced Humidity Sensing Response of SnO2/Silicon Nanopillar Array by UV Irradiation

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2141 ◽  
Author(s):  
Wei Li ◽  
Linlin Wang ◽  
Yun Cai ◽  
Peifeng Pan ◽  
Jinze Li ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Response Time ◽  
Specific Surface ◽  
Uv Irradiation ◽  
Recovery Time ◽  
Room Temperature ◽  
Uv Light ◽  
Humidity Sensing ◽  
Potential Applications ◽  
Humidity Sensitivity

In this work, a silicon nanopillar array was created with nanosphere lithography. SnO2 film was deposited on this nanostructure by magnetron sputtering to form an SnO2/silicon nanopillar array sensor. The humidity sensitivity, response time, and recovery time were all measured at room temperature (25 °C) with UV or without UV irradiation. As a result, the humidity sensitivity properties were improved by enlarging the specific surface area with ordered nanopillars and irradiating with UV light. These results indicate that nanostructure sensors have potential applications in the field of sensors.

scholarly journals Photo-Induced Super-hydrophilic Thin Films on Quartz Glass by UV Irradiation of Precursor Films Involving a Ti(IV) Complex at Room Temperature

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 348 ◽  
Author(s):  
Hsiang-Jung Wu ◽  
Kota Tanabe ◽  
Hiroki Nagai ◽  
Mitsunobu Sato
Keyword(s):  
Thin Films ◽  
Uv Irradiation ◽  
Quartz Glass ◽  
Room Temperature ◽  
Contact Angles ◽  
Chemical Components ◽  
Precursor Film ◽  
Dark Condition ◽  
Xps Spectra ◽  
Molecular Precursor

Photo-induced super-hydrophilic thin films were fabricated on a quartz glass substrate by ultraviolet (UV) irradiation of a molecular precursor film at room temperature. A molecular precursor film exhibiting high solubility to both ethanol and water was obtained by spin-coating a solution involving a Ti(IV) complex; this complex was prepared by the reaction of Ti(IV) alkoxide with butylammonium hydrogen oxalate and hydrogen peroxide in ethanol. Transparent and well-adhered amorphous thin films of 160–170 nm thickness were obtained by weak UV irradiation (4 mW·cm−2 at 254 nm) of the precursor films for over 4 h at room temperature. The resultant thin films exhibiting low refractive indices of 1.78–1.79 were mechanically robust and water-insoluble. The chemical components of the thin films were examined by means of Fourier transform-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) spectra, focusing on the presence of the original ligands. The super-hydrophilic properties (evaluated based on the water contact angles on the surfaces) of the thin films after being kept in a dark condition overnight emerged when the aforementioned UV-light irradiation was performed for 10 min. It was additionally clarified that the super-hydrophilicity can be photo-induced repeatedly by UV irradiation for 10 min (indicated by a contact angle smaller than 4°) even after the hydrophilic level of the thin films had once been lowered by being in a dark condition for 4 h.

Effect of UV Irradiation on Microlens Arrays Fabricated by Room Temperature Nanoimprinting Using Organic Spin-on-Glass

2008 ◽  
Vol 1 ◽  
pp. 067002 ◽  
Author(s):  
Ken-ichiro Nakamatsu ◽  
Makoto Okada ◽  
Chiaki Minari ◽  
Yoshiyuki Takeuchi ◽  
Noriaki Taneichi ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Room Temperature ◽  
Microlens Arrays
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