scholarly journals Modification of Track Etchedfluorinatea Films by Radiation Induced Graft Copolymerization

2009 ◽  
Vol 3 (2) ◽  
pp. 123-128
Author(s):  
Sunita Rattan ◽  
◽  
Inderjeet Kaur ◽  
Nitika Gupta ◽  
Devesh Kumar Avasthi ◽  
...  
Keyword(s):  
Total Dose ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Spectroscopic Techniques ◽  
Reaction Conditions ◽  
Force Microscopy ◽  
Atomic Force ◽  
Radiation Induced ◽  
Ftir Technique ◽  
Basic Characteristics

With the aim of improving the basic characteristics of Track Etched Membranes (TEMs), functionalization by graft copolymerization has been attempted in the present work. Thin films (25 μm) of poly(vinyl fluoride) (PVF) (Tedlar) were irradiated by swift heavy ions (110 MeV Si 8+ ). The irradiated films were chemically etched to form latent tracks. Atomic Force Microscopy (AFM) was used to ascertain the formation of latent tracks. Irradiation effects were studied using UV-visible spectroscopic techniques. The tracks were functionalized by gamma radiation induced grafting with 4-vinyl pyridine (4-VP). In order to anticipate the best grafting conditions, percentage of grafting was studied as a function of various reaction conditions such as (i) total dose, (ii) monomer concentration and (iii) amount of water. Maximum percentage of grafting (13.66 %) was obtained at a total dose of 57.024 kGy using 2 ml of 4-VP in 10 ml of water. The grafted films were characterized by FTIR technique

Breaking Down the Supramolecular Ensemble: Single-Molecule Studies of the Concentration Dependence of Main-Chain Supramolecular Polymer Molecular Weight Distributions on Surfaces

2010 ◽  
Vol 63 (4) ◽  
pp. 624
Author(s):  
Michael J. Serpe ◽  
Jason R. Whitehead ◽  
Stephen L. Craig
Keyword(s):  
Molecular Weight ◽  
Single Molecule ◽  
Monomer Concentration ◽  
Supramolecular Polymer ◽  
Force Microscopy ◽  
Molecular Weight Distributions ◽  
Atomic Force ◽  
Multi Stage ◽  
Single Molecule Studies ◽  
Supramolecular Ensemble

Single molecule atomic force microscopy (AFM) studies of oligonucleotide-based supramolecular polymers on surfaces are used to examine the molecular weight distribution of the polymers formed between a functionalized surface and an AFM tip as a function of monomer concentration. For the concentrations examined here, excellent agreement with a multi-stage open association model of polymerization is obtained, without the need to invoke additional contributions from secondary steric interactions at the surface.

scholarly journals Aliphatic Diacidic Long-Chain C16 Polyesters from 10,16-Dihydroxyhexadecanoic Acid Obtained from Tomato Residual Wastes

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1524 ◽  
Author(s):  
Arrieta-Baez ◽  
Hernández Ortíz ◽  
Terán ◽  
Torres ◽  
Gómez-Patiño
Keyword(s):  
Mass Spectrometry ◽  
Enzymatic Reaction ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Atomic Force ◽  
One Step ◽  
Long Chain ◽  
Polyester Film

10,16-dihydroxyhexadecanoic acid obtained from agroresidual tomato waste, was oxidized to produce 7-oxohexadecanedioic acid in good yield (>70%) and purified without oxidation side products in one step. Polycondensation with 1,8-octanediol, yielded the polyester (poly(ω-carboxyl PA-co-OD)) with Mw = 2155.15 and Mn = 1637.27. The best enzymatic reaction conditions to get the polyester were using lipase CAL-B (%-by-wt relative to monomer) in toluene as a solvent for 1 h at 60 °C. The poly(ω-carboxyl PA-co-OD) was characterized by 1H- and 13C-NMR, mass spectrometry (MALDI-TOF) and the polyester film formed with a Langmuir-Blodgett Trough was analyzed by means of spectroscopic ellipsometry and atomic force microscopy.

scholarly journals New Grafted Copolymers Carrying Betaine Units Based on Gellan and N-Vinylimidazole as Precursors for Design of Drug Delivery Systems

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5451
Author(s):  
Stefania Racovita ◽  
Nicolae Baranov ◽  
Ana Maria Macsim ◽  
Catalina Lionte ◽  
Corina Cheptea ◽  
...  
Keyword(s):  
Graft Copolymerization ◽  
Polymer Concentration ◽  
Monomer Concentration ◽  
Ammonium Persulfate ◽  
Nitrogen Atmosphere ◽  
Sustained Drug Release ◽  
Reaction Conditions ◽  
Grafted Polymer ◽  
Grafted Copolymer ◽  
Grafting Reaction

New grafted copolymers possessing structural units of 1-vinyl-3-(1-carboxymethyl) imidazolium betaine were obtained by graft copolymerization of N-vinylimidazole onto gellan gum followed by the polymer-analogous reactions on grafted polymer with the highest grafting percentage using sodium chloroacetate as the betainization agent. The grafted copolymers were prepared using ammonium persulfate/N,N,N′,N′ tetramethylethylenediamine in a nitrogen atmosphere. The grafting reaction conditions were optimized by changing one of the following reaction parameters: initiator concentration, monomer concentration, polymer concentration, reaction time or temperature, while the other parameters remained constant. The highest grafting yield was obtained under the following reaction conditions: ci = 0.08 mol/L, cm = 0.8 mol/L, cp = 8 g/L, tr = 4 h and T = 50 °C. The kinetics of the graft copolymerization of N-vinylimidazole onto gellan was discussed and a suitable reaction mechanism was proposed. The evidence of the grafting reaction was confirmed through FTIR spectroscopy, X-ray diffraction, 1H-NMR spectroscopy and scanning electron microscopy. The grafted copolymer with betaine structure was obtained by a nucleophilic substitution reaction where the betainization agent was sodium chloroacetate. Preliminary results prove the ability of the grafted copolymers to bind amphoteric drugs (cefotaxime) and, therefore, the possibility of developing the new sustained drug release systems.

scholarly journals Mechanical Characterization of a Dynamic and Tunable Methacrylated Hyaluronic Acid Hydrogel

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Matthew G. Ondeck ◽  
Adam J. Engler
Keyword(s):  
Hyaluronic Acid ◽  
Elastic Modulus ◽  
Monomer Concentration ◽  
Degree Of Polymerization ◽  
Force Microscopy ◽  
3T3 Fibroblasts ◽  
Atomic Force ◽  
Spread Area ◽  
Nih 3T3

Hyaluronic acid (HA) is a commonly used natural polymer for cell scaffolding. Modification by methacrylate allows it to be polymerized by free radicals via addition of an initiator, e.g., light-sensitive Irgacure, to form a methacrylated hyaluronic acid (MeHA) hydrogel. Light-activated crosslinking can be used to control the degree of polymerization, and sequential polymerization steps allow cells plated onto or in the hydrogel to initially feel a soft and then a stiff matrix. Here, the elastic modulus of MeHA hydrogels was systematically analyzed by atomic force microscopy (AFM) for a number of variables including duration of UV exposure, monomer concentration, and methacrylate functionalization. To determine how cells would respond to a specific two-step polymerization, NIH 3T3 fibroblasts were cultured on the stiffening MeHA hydrogels and found to reorganize their cytoskeleton and spread area upon hydrogel stiffening, consistent with cells originally cultured on substrates of the final elastic modulus.

scholarly journals Preparation and Optical Application of SiO2-TiO2 Composite Hardening Coatings with Controllable Refractive Index by Synchronous Polymerization

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 129
Author(s):  
Weiping Du ◽  
Shuting Cai ◽  
Yang Zhang ◽  
Huifang Chen
Keyword(s):  
Refractive Index ◽  
Titanium Isopropoxide ◽  
Hard Coatings ◽  
Reaction Conditions ◽  
Optical Lens ◽  
Force Microscopy ◽  
Hardness Tester ◽  
Hardening Coatings ◽  
Atomic Force ◽  
Particle Size Analyzer

The homogeneous SiO2-TiO2 composite sols were prepared by organic-inorganic synchronous polymerization with titanium isopropoxide and tetrabutyl silicate as precursor. The organic-inorganic composite hard coating with Si-O-Ti as the framework was prepared by adding compound crosslinkers (up-401) and 3-Methacryloxypropyltrimethoxysilane (KH-560). The structure of the coating and the hardened film were characterized by infrared spectrum, scanning electron microscopy, atomic force microscopy, particle size analyzer and thermogravimetry. The refractive index, transmittance and hardness of the hardened film were measured by ellipsometry, UV-Vis spectrophotometer and hardness tester. By adjusting the ratio of Si/Ti and optimizing the reaction conditions, the hardness of the hardened film could reach 6H, and the refractive index could be adjusted from 1.55 to 1.76. At the same time, the application of hard coatings on the surface of optical lens were studied.

Integrated atomic force microscopy and x-ray irradiation for in situ characterization of radiation-induced processes

2021 ◽  
Vol 92 (11) ◽  
pp. 113701
Author(s):  
Shawn L. Riechers ◽  
Nikolai Petrik ◽  
John S. Loring ◽  
Mark K. Murphy ◽  
Carolyn I. Pearce ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
In Situ Characterization ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Radiation Induced

Spatial Distribution of Radiation-Induced Double-Strand Breaks in Plasmid DNA as Resolved by Atomic Force Microscopy

2005 ◽  
Vol 164 (6) ◽  
pp. 755-765 ◽  
Author(s):  
Dalong Pang ◽  
James E. Rodgers ◽  
Barry L. Berman ◽  
Sergey Chasovskikh ◽  
Anatoly Dritschilo
Keyword(s):  
Atomic Force Microscopy ◽  
Spatial Distribution ◽  
Plasmid Dna ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Force Microscopy ◽  
Atomic Force ◽  
Radiation Induced

Structural analysis of heavy ion radiation-induced chromosome aberrations by atomic force microscopy

2001 ◽  
Vol 48 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Masahiro Murakami ◽  
Masako Minamihisamatsu ◽  
Koki Sato ◽  
Isamu Hayata
Keyword(s):  
Atomic Force Microscopy ◽  
Structural Analysis ◽  
Chromosome Aberrations ◽  
Heavy Ion ◽  
Force Microscopy ◽  
Atomic Force ◽  
Radiation Induced ◽  
Heavy Ion Radiation

scholarly journals Laser spectroscopic technique for direct identification of a single virus I: FASTER CARS

2020 ◽  
Vol 117 (45) ◽  
pp. 27820-27824 ◽  
Author(s):  
Volker Deckert ◽  
Tanja Deckert-Gaudig ◽  
Dana Cialla-May ◽  
Jürgen Popp ◽  
Roland Zell ◽  
...  
Keyword(s):  
Clinical Sample ◽  
H1n1 Influenza ◽  
Spectroscopic Technique ◽  
Spectroscopic Techniques ◽  
Force Microscopy ◽  
Virus Particles ◽  
Detection Techniques ◽  
Atomic Force ◽  
Enhanced Resolution ◽  
Anti Stokes

From the famous 1918 H1N1 influenza to the present COVID-19 pandemic, the need for improved viral detection techniques is all too apparent. The aim of the present paper is to show that identification of individual virus particles in clinical sample materials quickly and reliably is near at hand. First of all, our team has developed techniques for identification of virions based on a modular atomic force microscopy (AFM). Furthermore, femtosecond adaptive spectroscopic techniques with enhanced resolution via coherent anti-Stokes Raman scattering (FASTER CARS) using tip-enhanced techniques markedly improves the sensitivity [M. O. Scully,et al.,Proc. Natl. Acad. Sci. U.S.A.99, 10994–11001 (2002)].

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