scholarly journals Polyaniline Deposition on the Surface of Cotton Fibers: Structural Studies, Swelling Behavior, and Water Absorption Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Tesfamariam Teklu ◽  
Teklit Kidane Gebremedhin ◽  
Amanual Hadera Tesfay ◽  
Asfaw Gebretsadik Gebru ◽  
Ykalo Hadush Desta ◽  
...  
Keyword(s):  
Water Absorption ◽  
Electromagnetic Interference ◽  
Structural Changes ◽  
Natural Fibers ◽  
Control Sample ◽  
Cotton Fibers ◽  
Surface Deposition ◽  
Ft Ir ◽  
Effect Of Surface

Polyaniline-modified natural fibers have been recognized as promising candidates for conductive clothes, UV protection, and electromagnetic interference shielding. Hence, the purpose of this study was to investigate the effect of surface deposition of cotton fibers using polyaniline via in situ polymerization, and preceding structural changes were further screened by FT-IR, UV-Vis, TGA, SEM/EDX, and conductivity in comparison with bare cotton fibers used as the control sample. Polyaniline was introduced on the surface of cotton fibers as a conductive form, which was confirmed by electrical conductivity (1.54 × 10−4 Scm−1) equivalent to semiconductor materials. Detection of particular peaks at NKα 0.379 keV and ClKα 2.621 keV from EDX analysis revealed the introduction of nitrogen and chlorine, respectively. Polyaniline deposition on the cotton surface was successful to introduce hydrophobic environment to the system to enhance resistance to water absorption meaningfully.

scholarly journals Structural changes of Au–Cu bimetallic catalysts in CO oxidation: In situ XRD, EPR, XANES, and FT-IR characterizations

2011 ◽  
Vol 278 (2) ◽  
pp. 288-296 ◽  
Author(s):  
Xiaoyan Liu ◽  
Aiqin Wang ◽  
Lin Li ◽  
Tao Zhang ◽  
Chung-Yuan Mou ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Bimetallic Catalysts ◽  
Structural Changes ◽  
In Situ Xrd ◽  
Ft Ir

scholarly journals Characteristic variations of bacterial nanocellulose incorporated with different cellulosic additives

2021 ◽  
Author(s):  
Won Yeong Bang ◽  
Dong Hyun Kim ◽  
Mi Dan Kang ◽  
Jungwoo Yang ◽  
Taelin Huh ◽  
...  
Keyword(s):  
Structural Changes ◽  
Binding Protein ◽  
High Sensitivity ◽  
Surface Characteristics ◽  
X Ray Diffraction ◽  
Bacterial Nanocellulose ◽  
Feasible Option ◽  
Ft Ir ◽  
Cellulose Binding

Abstract Bacterial cellulose (BNC) is a promising biocompatible material. Improvements of the BNC production and its surface characteristics should be attained to make it commercially viable. In this study, in-situ fermentation and production of BNC by addition of different cellulosic substrates such as Avicel and carboxymethylcellulose (CMC) were performed using Komagataeibacter sp. SFCB22-18. The addition of cellulosic substrates improved BNC production by a maximum of about 5 times and slightly modified its structural properties. The changes in morphological and structural changes of BNC were investigated by using Fourier transform-infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Furthermore, a unique biological analysis approach for quantifying the surface crystallinity of the BNC surface was applied using a type-A cellulose-binding protein, CtCBD3. This result shows that since Avicel and CMC may attach on the microfibrils during the production or crystallization of BNC, cellulose-binding protein could be a feasible option for identifying the crystalline properties of BNC with high sensitivity.

Effect of surface modification on the electrical properties of TiO2 and SnO2 nanopowders

1997 ◽  
Vol 501 ◽  
Author(s):  
Fabienne Chancel ◽  
Jérôme Tribout ◽  
Marie-Isabelle Baraton
Keyword(s):  
Surface Modification ◽  
Electrical Properties ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Free Carriers ◽  
Conductivity Variation ◽  
Ft Ir ◽  
Effect Of Surface ◽  
Ft Ir Spectroscopy

ABSTRACTThe surface modification of titania and tin dioxide nanopowders by hexamethyldisilazane and hexamethyldisiloxane grafting has been followed in situ by FT-IR spectroscopy. A grafting mechanism is proposed for both compounds and the formation of new surface species is discussed. Since TiO2 and SnO2 are widely used in chemical gas sensors due to their electrical properties, the respective behaviors of the non-grafted and grafted samples in reducing (CO) environment as well as the humidity effects are compared. Because the transmitted IR energy depends on the concentration of the free carriers, a correlation between the electrical conductivity variation and the perturbation of the IR spectra is attempted.

FT-IR microspectroscopic analysis of diseased white matter brain tissues

1995 ◽  
Vol 53 ◽  
pp. 968-969
Author(s):  
Steven M. Le Vine ◽  
David L. Wetzel
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Twitcher Mouse ◽  
Grid Pattern ◽  
Marked Contrast ◽  
Spatially Resolved ◽  
Ft Ir ◽  
Ir Microspectroscopy ◽  
Chemical Evidence

In situ FT-IR microspectroscopy has allowed spatially resolved interrogation of different parts of brain tissue. In previous work the spectrrscopic features of normal barin tissue were characterized. The white matter, gray matter and basal ganglia were mapped from appropriate peak area measurements from spectra obtained in a grid pattern. Bands prevalent in white matter were mostly associated with the lipid. These included 2927 and 1469 cm-1 due to CH2 as well as carbonyl at 1740 cm-1. Also 1235 and 1085 cm-1 due to phospholipid and galactocerebroside, respectively (Figs 1and2). Localized chemical changes in the white matter as a result of white matter diseases have been studied. This involved the documentation of localized chemical evidence of demyelination in shiverer mice in which the spectra of white matter lacked the marked contrast between it and gray matter exhibited in the white matter of normal mice (Fig. 3).The twitcher mouse, a model of Krabbe’s desease, was also studied. The purpose in this case was to look for a localized build-up of psychosine in the white matter caused by deficiencies in the enzyme responsible for its breakdown under normal conditions.

Nucleation and initial growth of Pd2Si crystals on Si(111)

1993 ◽  
Vol 51 ◽  
pp. 844-845
Author(s):  
Xianghong Tong ◽  
Oliver Pohland ◽  
J. Murray Gibson
Keyword(s):  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Initial Growth ◽  
Surface And Interface ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Initial Stage ◽  
Effect Of Surface

The nucleation and initial stage of Pd2Si crystals on Si(111) surface is studied in situ using an Ultra-High Vacuum (UHV) Transmission Electron Microscope (TEM). A modified JEOL 200CX TEM is used for the study. The Si(111) sample is prepared by chemical thinning and is cleaned inside the UHV chamber with base pressure of 1x10−9 τ. A Pd film of 20 Å thick is deposited on to the Si(111) sample in situ using a built-in mini evaporator. This room temperature deposited Pd film is thermally annealed subsequently to form Pd2Si crystals. Surface sensitive dark field imaging is used for the study to reveal the effect of surface and interface steps.The initial growth of the Pd2Si has three stages: nucleation, growth of the nuclei and coalescence of the nuclei. Our experiments shows that the nucleation of the Pd2Si crystal occurs randomly and almost instantaneously on the terraces upon thermal annealing or electron irradiation.

scholarly journals Effects on Lignin Redistribution in Eucalyptus globulus Fibres Pre-Treated by Steam Explosion: A Microscale Study to Cellulose Accessibility

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 507
Author(s):  
Eduardo Troncoso-Ortega ◽  
Rosario del P. Castillo ◽  
Pablo Reyes-Contreras ◽  
Patricia Castaño-Rivera ◽  
Regis Teixeira Mendonça ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Eucalyptus Globulus ◽  
Steam Explosion ◽  
Laser Scanning ◽  
Structural Changes ◽  
Micro Particles ◽  
Cellulose Accessibility ◽  
Ft Ir ◽  
Enzymatic Accessibility ◽  
Physical And Chemical

The objective of this study was to investigate structural changes and lignin redistribution in Eucalyptus globulus pre-treated by steam explosion under different degrees of severity (S0), in order to evaluate their effect on cellulose accessibility by enzymatic hydrolysis. Approximately 87.7% to 98.5% of original glucans were retained in the pre-treated material. Glucose yields after the enzymatic hydrolysis of pre-treated material improved from 19.4% to 85.1% when S0 was increased from 8.53 to 10.42. One of the main reasons for the increase in glucose yield was the redistribution of lignin as micro-particles were deposited on the surface and interior of the fibre cell wall. This information was confirmed by laser scanning confocal fluorescence and FT-IR imaging; these microscopic techniques show changes in the physical and chemical characteristics of pre-treated fibres. In addition, the results allowed the construction of an explanatory model for microscale understanding of the enzymatic accessibility mechanism in the pre-treated lignocellulose.

Roughened gold electrode for in situ SERS analysis of structural changes accompanying the doping process of polyaniline in acidic aqueous media

2021 ◽  
Vol 882 ◽  
pp. 115034
Author(s):  
A. El Guerraf ◽  
M. Bouabdallaoui ◽  
Z. Aouzal ◽  
S. Ben Jadi ◽  
N.K. Bakirhan ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Structural Changes ◽  
Aqueous Media

scholarly journals Experimental and Theoretical Studies of Sonically Prepared Cu–Y, Cu–USY and Cu–ZSM-5 Catalysts for SCR deNOx

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ultrasonic Irradiation ◽  
Active Phase ◽  
Spectroscopic Studies ◽  
In Situ Drifts ◽  
Ft Ir ◽  
Diffuse Reflectance Infrared ◽  
Experimental And Theoretical Studies

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).

scholarly journals Synthesis of Poly(methacrylic acid-co-butyl acrylate) Grafted onto Functionalized Carbon Nanotube Nanocomposites for Drug Delivery

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 533 ◽  
Author(s):  
Josué A. Torres-Ávalos ◽  
Leonardo R. Cajero-Zul ◽  
Milton Vázquez-Lepe ◽  
Fernando A. López-Dellamary ◽  
Antonio Martínez-Richa ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Methacrylic Acid ◽  
Butyl Acrylate ◽  
Chemical Vapor ◽  
Vis Spectroscopy ◽  
Ir And Raman Spectroscopies ◽  
Ft Ir

Design of a smart drug delivery system is a topic of current interest. Under this perspective, polymer nanocomposites (PNs) of butyl acrylate (BA), methacrylic acid (MAA), and functionalized carbon nanotubes (CNTsf) were synthesized by in situ emulsion polymerization (IEP). Carbon nanotubes were synthesized by chemical vapor deposition (CVD) and purified with steam. Purified CNTs were analyzed by FE-SEM and HR-TEM. CNTsf contain acyl chloride groups attached to their surface. Purified and functionalized CNTs were studied by FT-IR and Raman spectroscopies. The synthesized nanocomposites were studied by XPS, 13C-NMR, and DSC. Anhydride groups link CNTsf to MAA–BA polymeric chains. The potentiality of the prepared nanocomposites, and of their pure polymer matrices to deliver hydrocortisone, was evaluated in vitro by UV–VIS spectroscopy. The relationship between the chemical structure of the synthesized nanocomposites, or their pure polymeric matrices, and their ability to release hydrocortisone was studied by FT-IR spectroscopy. The hydrocortisone release profile of some of the studied nanocomposites is driven by a change in the inter-associated to self-associated hydrogen bonds balance. The CNTsf used to prepare the studied nanocomposites act as hydrocortisone reservoirs.

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