This study synthesized pH- and temperature-responsive magnetic nanoparticles (MNPs) by grafting a block copolymer of poly(itaconic acid) and poly(N-isopropylacrylamide) (PIA-b-PNIPAM) onto iron oxide nanoparticles via atom transfer radical polymerization. Characterization using techniques such as transmission electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy demonstrated the successful synthesis and responsiveness of the Fe3O4@PIA-b-PNIPAM nanocomposites to changes in pH and temperature. The nanoparticles have potential applications for stimuli-responsive drug delivery and
Electrooxidation of methanol on carbon supported pt ru nanocatalysts prepared...suresh899
Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electro-oxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.
Partial Molar Volumes of Tetra alkyl ammonium salts in 10%(W/W) 2-(Ethoxy) et...Premier Publishers
In this article densities and apparent molar volumes of Tetra alkyl ammonium bromide salts ( ) in 10% (W/W) 2-(Ethoxy) ethanol-water mixture is studied at 30o, 35o and 40oC. Partial molar volumes are divided into ionic components using different methods such as Conway et al. and Jolicoeur et al. The results are compared with the values of partial molar volumes of ions reported in literature for pure water. Decrease in hydrophobic hydration is noticed. This may be due to the addition of co-solvent 2-(Ethoxy) ethanol (confirming the conclusions drawn from our viscosity studies that in 2-(Ethoxy) ethanol-water mixture, the structuredness of water is reduced by the breaking of hydrogen bonds). The values are divided into and . Making use of the Padova’s equation values of salts are calculated. These are also divided into ionic contributions. Dimensions of ions have been calculated to understand solvation behavior. It is shown that the classification of salts into structure makers and structure breakers on the basis of the sign of is not valid for the present water rich mixed solvent system.
Electrooxidation of methanol on carbon supported pt ru nanocatalysts prepared...suresh899
Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electro-oxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.
Partial Molar Volumes of Tetra alkyl ammonium salts in 10%(W/W) 2-(Ethoxy) et...Premier Publishers
In this article densities and apparent molar volumes of Tetra alkyl ammonium bromide salts ( ) in 10% (W/W) 2-(Ethoxy) ethanol-water mixture is studied at 30o, 35o and 40oC. Partial molar volumes are divided into ionic components using different methods such as Conway et al. and Jolicoeur et al. The results are compared with the values of partial molar volumes of ions reported in literature for pure water. Decrease in hydrophobic hydration is noticed. This may be due to the addition of co-solvent 2-(Ethoxy) ethanol (confirming the conclusions drawn from our viscosity studies that in 2-(Ethoxy) ethanol-water mixture, the structuredness of water is reduced by the breaking of hydrogen bonds). The values are divided into and . Making use of the Padova’s equation values of salts are calculated. These are also divided into ionic contributions. Dimensions of ions have been calculated to understand solvation behavior. It is shown that the classification of salts into structure makers and structure breakers on the basis of the sign of is not valid for the present water rich mixed solvent system.
Hydrogen bonding and molecular design (BrazMedChem 2010)Peter Kenny
These are the slides that I used at BrazMedChem 2010 in Ouro Preto and it is essentially the same presentation that I'd done a few weeks earlier at EuroQSAR.
ABSTRACT:
Benzimidazole is a fused heterocyclic ring containing two nitrogen at position 1 and 3 in five member ring. This ring have large spectrum of biological activity specifically antimicrobial activity. We synthesis benzimidazole derivatives which have great percentage yield than reported and develop synthetic scheme that less time consuming with high purity of compound as well as no need of any kind of chromatography for purification. all compound was recrystallized with ethanol. We develop economical method of synthesis of benimidazole derivatives also characterization was carried out by IR and H1 NMR (CDCl3), Physical Constant, Solubility, Refractive Index. Benzimidazole derivative biologically evaluated on different microorganism. In the result gram negative and gram positive bacteria was Inhibited.
In this research in order to produce blood sugar biosensor, an appropriate
membrane for glucose oxidase immobilization by using nanofibers created from
polymers of polyacrylic acid and starch are studied. They are biocompatible and
biodegradable respectively and were prepared by electro-spinning method for
nanofiber fabrication. Dimethylformamide and distilled water were used as solvent for
PAA and starch respectively to get a homogeneous solution. Because nanofibers made
of polyacrylic acid-starch face with enzymes, due to its extremely high hydrophilic
‘OH’ groups may lose their cohesion, crosslinking as chemical surface modification
and for better enzyme immobilization, non-thermal plasma surface modification using
atmospheric pressure Dielectric Barrier Discharge (DBD) were used. Crosslinking was
carried out by APTMS and Glutaraldehyde (GA). The effect of electro-spinning process
variables on morphology of nanofibers was examined by Scanning Electron
Microscopy (SEM). Nanofibers structure and chemical composition to demonstrate
the successful linking and immobilization of enzymes in the composite membrane was
obtained by Fourier Transform Infrared spectroscopy (FTIR) and improved thermal
stability of nanofibers in presence of enzyme and surface modifications was
determined by Thermal Gravimetric Analysis (TGA).
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Interaction of Components in Molecular Optoelectronics for the Next Generati...Scientific Review SR
The interaction of molecular optoelectronic components on the molecular scale were studied where
the solvent shell indicating the influence of the medium was found to be surprisingly small. The transport of
energy as resonant energy transfer covers distances of about 5 nm and was shown not to proceed by a simple to
dipole dipole interaction with typical restrictions, but by a more complex mechanism. Furthermore, a novel -type of
far-reaching interactions of electronically excited structures until macroscopic dimensions were fond and may be
applied for addressing molecular structures by conventional electronics
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Si-Imidazole-HSO4 Functionalized Magnetic Fe3O4 Nanoparticles as an Efficient...Iranian Chemical Society
An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.
Hydrogen bonding and molecular design (BrazMedChem 2010)Peter Kenny
These are the slides that I used at BrazMedChem 2010 in Ouro Preto and it is essentially the same presentation that I'd done a few weeks earlier at EuroQSAR.
ABSTRACT:
Benzimidazole is a fused heterocyclic ring containing two nitrogen at position 1 and 3 in five member ring. This ring have large spectrum of biological activity specifically antimicrobial activity. We synthesis benzimidazole derivatives which have great percentage yield than reported and develop synthetic scheme that less time consuming with high purity of compound as well as no need of any kind of chromatography for purification. all compound was recrystallized with ethanol. We develop economical method of synthesis of benimidazole derivatives also characterization was carried out by IR and H1 NMR (CDCl3), Physical Constant, Solubility, Refractive Index. Benzimidazole derivative biologically evaluated on different microorganism. In the result gram negative and gram positive bacteria was Inhibited.
In this research in order to produce blood sugar biosensor, an appropriate
membrane for glucose oxidase immobilization by using nanofibers created from
polymers of polyacrylic acid and starch are studied. They are biocompatible and
biodegradable respectively and were prepared by electro-spinning method for
nanofiber fabrication. Dimethylformamide and distilled water were used as solvent for
PAA and starch respectively to get a homogeneous solution. Because nanofibers made
of polyacrylic acid-starch face with enzymes, due to its extremely high hydrophilic
‘OH’ groups may lose their cohesion, crosslinking as chemical surface modification
and for better enzyme immobilization, non-thermal plasma surface modification using
atmospheric pressure Dielectric Barrier Discharge (DBD) were used. Crosslinking was
carried out by APTMS and Glutaraldehyde (GA). The effect of electro-spinning process
variables on morphology of nanofibers was examined by Scanning Electron
Microscopy (SEM). Nanofibers structure and chemical composition to demonstrate
the successful linking and immobilization of enzymes in the composite membrane was
obtained by Fourier Transform Infrared spectroscopy (FTIR) and improved thermal
stability of nanofibers in presence of enzyme and surface modifications was
determined by Thermal Gravimetric Analysis (TGA).
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Interaction of Components in Molecular Optoelectronics for the Next Generati...Scientific Review SR
The interaction of molecular optoelectronic components on the molecular scale were studied where
the solvent shell indicating the influence of the medium was found to be surprisingly small. The transport of
energy as resonant energy transfer covers distances of about 5 nm and was shown not to proceed by a simple to
dipole dipole interaction with typical restrictions, but by a more complex mechanism. Furthermore, a novel -type of
far-reaching interactions of electronically excited structures until macroscopic dimensions were fond and may be
applied for addressing molecular structures by conventional electronics
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Si-Imidazole-HSO4 Functionalized Magnetic Fe3O4 Nanoparticles as an Efficient...Iranian Chemical Society
An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.
In this work, the synthetic hydroxyapatite (HAP) was studied using different preparation routes to decrease the crystal size and to study the temperature effect on the HAP nano-sized hydroxyapatite crystallization. X-ray diffraction (XRD) analysis indicated that all samples were composed by crystalline and amorphous phases . The sample with greater quantity of amorphous phase (40% of total mass) was studied. The nano-sized hydroxyapatite powder was heated and studied at 300, 500, 700, 900 and 1150 °C. All samples were characterized by XRD and their XRD patterns refined using the Rietveld method. The crystallites presented an anisotropic form, being larger in the [001] direction. It was observed that the crystallite size increased continuously with the heating temperature and the eccentricity of the ellipsoidal shape changed from 2.75 at 300 °C to 1.94, 1.43, 1.04 and 1.00 respectively at 500, 700, 900 and 1150 °C. In order to better characterize the morphology of the HAP the samples were also examined using atomic force microscopy (AFM), infrared spectrometry (IR) and thermogravimetric analysis (TGA).
The study of intermolecular interactions at interfaces is essential for a number of applications, in addition
to the understanding of mechanisms involved in sensing and biosensing with liquid samples. There are,
however, only a few methods to probe such interfacial phenomena, one of which is the atomic force
spectroscopy (AFS) where the force between an atomic force microscope tip and the sample surface is
measured. In this study, we used AFS to estimate adhesion forces for a nanostructured film of poly(oethoxyaniline)
(POEA) doped with various acids, in measurements performed in air. The adhesion force
was lower for POEA doped with inorganic acids, such as HCl and H2SO4, than with organic acids, because
the counterions were screened by the ethoxy groups. Significantly, the morphology of POEA both in the
film and in solution depends on the doping acid. Using small-angle X-ray scattering (SAXS) we observed
that POEA dissolved in amixture of dimethyl acetamide exhibits a more extended coil-like conformation,
with smaller radius of gyration, than for POEA in water, as in the latter POEA solubility is lower. In AFS
measurements in a liquid cell, the force curves for a POEA layer displayed an attractive region for pH 5
due to van der Waals interactions, with no contribution from a double-layer since POEA was dedoped. In
contrast, for pH 3, POEA was doped and the repulsive double-layer force dominated. With AFS one is
therefore able to correlate molecular-level interactions with doping and morphology of semiconducting
polymers.
Crimson publishers-Biosynthesis of the Fe3O4 Nanoparticles Using Acacia Nilot...CrimsonpublishersTTEFT
Biosynthesis of the Fe3O4 Nanoparticles Using Acacia Nilotica Leaf Extract and their Effect on Degradation of Congo Red Dye in Aqueous Solution by Vasantha Jyothi NVV* and Venkateswarlu P* in Trends in Textile Engineering & Fashion Technology
Experimental and theoretical investigations of some pyrazolo-pyrimidine deriv...Al Baha University
The anticorrosion performance of three pyrazolo-pyrimidine derivatives, namely, 4-amino pyrazolo-pyrimidine
(APP), 4-hydroxy pyrazolo-pyrimidine (HPP), and 4-mercapto pyrazolo-pyrimidine (MPP) on copper in 0.5M
H2SO4 solution have been investigated using electrochemical, surface analysis, as well as theoretical techniques.
The results indicate that these inhibitors have largely inhibited the corrosion of copper and the inhibition efficiency
increased with increasing concentration. Moreover, the inhibitors adsorb on copper surface following
Langmuir adsorption isotherm. XPS analysis were performed for describing the bonding characteristics between
inhibitors and copper substrate. Furthermore, DFT and molecular dynamics simulation calculations were applied
to further explain the anti-corrosion mechanism.
Mechanistic Aspects of Oxidation of P-Bromoacetophen one by Hexacyanoferrate ...IJERA Editor
The kinetics of oxidation of p-bromoacetophenone by hexacyanoferrate (III) has been studied in alkaline
medium. The order of reaction with respect of both acetophenone and hexacynoferrate (III) has been found to be
unity. The rate of reaction increases with increase in the concentration of sodium hydroxide.On addition of
neutral KCl, reaction rate increases. The effects of solvent and temperature have been also studied. The product
p-bromophenyl glyoxal have been characterized by IR studies.
Mechanistic Aspects of Oxidation of P-Bromoacetophen one by Hexacyanoferrate ...
PNIPAM-b-PMAA Poster
1. [1] C. de las H. Alarcon, S. Pennadam, C. Alexander, Stimuli responsive polymers for biomedical applications, Chem.
Soc. Rev. 34 (2005) 276–285. doi:10.1039/B406727D.
[2] Mingwu Shen and Hongdong Cai and Xifu Wang and Xueyan Cao and Kangan Li and Su He Wang and Rui Guo
and Linfeng Zheng and Guixiang Zhang and Xiangyang Shi, Facile one-pot preparation, surface functionalization, and
toxicity assay of APTS-coated iron oxide nanoparticles, Nanotechnology. 23 (2012) 105601.
[3] K. Matyjaszewski, J. Spanswick, Controlled/living radical polymerization, Mater. Today. 8 (2005) 26–33.
doi:10.1016/S1369-7021(05)00745-5.
[4] R. Pelton, Poly(N-isopropylacrylamide) (PNIPAM) is never hydrophobic, J. Colloid Interface Sci. 348 (2010) 673–
674. doi:10.1016/j.jcis.2010.05.034.
[5] M. Jaiswal, A. Pradhan, R. Banerjee, D. Bahadur, Dual pH and temperature stiumuli-responsive magnetic
nanohydrogels for thermo-chemotherapy, Journal of Nanoscience and Nanotechnology, volume 14 issue 6.
Multifunctional Nanocomposites Comprised of Magnetic Nanoparticles Grafted with pH and
Temperature Responsive Polymer
Swati Kumari*, Cayla Cook**, Evan Prehn*, Erick S. Vasquez***, Keisha B. Walters*
*Dave C. Swalm School of Chemical Engineering, Mississippi State University
**Department of Civil and Environmental Engineering, Mississippi State University
*** Department of Chemical and Materials Engineering, University of Dayton
Acknowledgments
This research was supported in part by the National Science Foundation (IIA-1430364, EPS-0903787, CBET-1403872). We appreciate I2AT at Mississippi State University for TEM imaging assistance.
Abstract
Stimuli responsive polymers (SRPs) have been of great interest in the last
few decades because of their potential in biomedical and environmental
applications. When SRPs are grafted from surface-modified magnetic-core
nanoparticles, they can be utilized for drug delivery and magnetic
resonance imaging. In this study, a one-step 3-
aminopropyltrimethoxysilane (APTS) hydrothermal approach was used to
synthesize APTS-coated iron oxide (Fe3O4@APTS) nanoparticles with
reactive surface amine groups. Using two successive surface initiated
atom transfer radical polymerizations (SI-ATRP), a pH and temperature
responsive block copolymer, poly-(itaconic acid)-b-poly(N-
isopropylacrylamide) (Fe3O4@PIA-b-PNIPAM) were grown from the
surface of Fe3O4@APTS. The nanocomposite consisting of a magnetic
nanoparticle (MNP) core and a polymer shell were characterized over a
range of temperature and pH using transmission electron microscopy
(TEM), light scattering, zeta potential, and Fourier transform infrared
spectroscopy (FTIR) to verify particle morphology, size distribution, charge,
and chemical composition. Results showed a successful synthesis, and
the resultant Fe3O4@PIA-b-PNIPAM demonstrated temperature and pH
responsiveness.
Introduction
Currently biomedical uses for magnetic nanoparticles includes drug
delivery, imaging and targeting [1]. Stimuli responsive polymers, or ‘smart’
polymers, can be grafted from MNPs via SI-ATRP to add polymers with
well-controlled molecular weight, chemical composition, and architecture
[2, 3]. Furthermore, PIA-b-NIPAM is of particular interest since it has
significant relevance for biomedical applications due to its lower critical
solubility temperature (LCST) of 32 °C [4], similar to human body
temperature. It’s potential has been highlighted in recent medical
applications [5].
Materials & Methods
Magnetic nanoparticles were synthesized through a hydrothermal reaction,
followed by a sequence of ATRP reactions to produce Fe3O4@PIA-b-
NIPAM , and characterized with:
Transmission electron microscopy (TEM)
Dynamic light scattering (DLS)
Fourier transform infrared (FITR) spectroscopy.
Results and Discussion
References
Conclusions
The structure, morphology, composition, and surface properties of
the formed particles were characterized by TEM, FTIR, and dynamic
light scattering measurements. A pH- and thermo-responsive block
copolymer comprised of PIA and PNIPAM was successfully
polymerized from the surface of nanoparticles.
FTIR, TEM, and DLS was used to characterize the polymers and
showed that the modified MNPs were well dispersed and stable in
water as well as some organic solvents. In particular, these
thermoresponsive and pH responsive polymers can be used in smart
drug delivery and other biomedical applications that is guided by
external stimuli.
Experimental Scheme
Fourier Transform Infrared Spectroscopy (FTIR)
❖ Transmission Electron Microscopy (TEM)
TEM image of (a) Fe3O4@APTS, (b) Fe3O4@APTS-PIA, and (c,d) Fe3O4@APTS-PIA-b-PNIPAM.
(a) The effective diameter of Fe3O4@APTS is ~300 nm. (b) The effective diameter of Fe3O4@APTS-
PIA more than doubles to ~800 nm. The grafted stimuli responsive polymer is visible around the
MNP. (c) Uniform nanocomposite size (narrow polydispersity) and effective diameter of the block
copolymer-modified ferrofluid/MNPs are shown. No nanoparticle agglomeration was observed. (d) A
magnified image of Fe3O4@APTS-PIA-b-PNIPAM shows an effective diameter of ~1000 nm (or ~1
micron).
❖ Dynamic Light Scattering (DLS)
DLS analysis was conducted on a dilute solution of approximately 1 μL of
Fe3O4@PIA-b-PNIPAM in a 3 mL solution with pH varying from 2 to 12.
Next, these samples were analyzed from 25 °C to 45 °C. DLS allows for
the measurement of the effective particle diameter and polydispersity.
At pH 12, pH 7, and pH 2—comprising the extreme and neutral pH values examined—all effective
diameters began < 600 nm. Previous DLS data denoted the effective hydrodynamic diameter at ~1100
nm; therefore, the PIA-b-PNIPAM coating was in a contracted state. Results show that at pH 10 the
polymer shell expands initially and then contracts at higher temperatures, matching the expected LCST
behavior.
0
200
400
600
800
1000
1200
1400
1600
25 27 29 31 33 35 37 39 41 43 45
EffectiveDiameter(nm)
Temperature (C)
pH 2
pH 4
pH 7
pH 10
pH 12
FTIR spectra of Fe3O4@APTS nanoparticles (blue spectrum) and Fe3O4@APTS-PIA-b-PNIPAM (red
spectrum). The white region indicates the regions for peaks assigned to hydroxyl, amine, alkane, and
carbonyl functional groups which matches the expected compositions of these SRP-MNP samples.
FTIR data characterizes the chemical functional groups present in the
sample using absorbance of infrared light.
TEM analysis allows for the visual interrogation of the samples on the
micro- to nano-scale in order to examine particle shape, polydispersity,
and other characteristics.
Sample Effective Hydrodynamic Diameter
Fe3O4@APTS 208.5 ± 2.7 nm
Fe3O4@PIA 880.9 ± 8.2 nm
Fe3O4@PIA-b-PNIPAM 1164.1 ± 63.1 nm
(a)
(d)(c)
(b)
NHO
( )n
COOH
COOH
( )n
Polymer and Surface
Engineering
Laboratory
(PolySEL)
http://www.polysel.che.msstate.edu//