scholarly journals Electrochemically Obtained Polysulfonates Doped Poly(3,4-ethylenedioxythiophene) Films—Effects of the Dopant’s Chain Flexibility and Molecular Weight Studied by Electrochemical, Microgravimetric and XPS Methods

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2438
Author(s):  
Vladimir Lyutov ◽  
Varvara Kabanova ◽  
Oxana Gribkova ◽  
Alexander Nekrasov ◽  
Vessela Tsakova
Keyword(s):  
Molecular Weight ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Point Of View ◽  
Acid Form ◽  
Salt Form ◽  
Flexible Chain ◽  
Chain Flexibility ◽  
Redox Transitions ◽  
Solvent Molecules

Electrochemically synthesized poly(3,4,-ethylenedioxythiophene) (PEDOT) films obtained in the presence of eight different polysulfonate dopants are comparatively studied by means of electrochemical quartz crystal microbalance (EQCM) and X-ray Photoelectron Spectroscopy (XPS). Differences with respect to oxidation and doping levels (OL and DL), polymerization efficiency and redox behavior are revealed based on the interplay of three factors: the type of the dopant (acid or salt form), flexibility of the polysulfonate chains and molecular weight of the polysulfonate species. For the rigid- and semi-rigid-chain dopants, use of the salt form results in higher OL and DL values and substantial involvement of solvent molecules in the course of polymerization and redox transitions whereas in the presence of their acid form compact PEDOT films with minor ionic-solvent fluxes upon redox transitions are formed. In contrast, use of the salt form of the flexible chain polysulfonates results in PEDOT with lower OL and DL in comparison to the corresponding acid form. Significant effects are observed when comparing flexible chain dopants with different molecular weights. From a practical point of view the present investigations demonstrate the large scope of possibilities to influence some basic properties of PEDOT (Ol and DL, intensity and type of the ionic and solvent fluxes upon redox transition) depending on the used polysulfonate dopants.

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

scholarly journals Multiplicity of Active-Site in Heterogeneous Ziegler-Natta Catalyst and Its Correlation with Polymer Microstructure

1970 ◽  
Vol 46 (4) ◽  
pp. 487-494
Author(s):  
ATM Kamrul Hasan
Keyword(s):  
Molecular Weight ◽  
Computer Simulation ◽  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Chain Structure ◽  
Surface Complexes ◽  
Polymer Microstructure ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

Multiplicity of active-site in heterogeneous Ziegler-Natta catalysts and its correlation with polymer microstructure was studied through the surface structure analysis of catalyst by computer simulation of X-ray Photoelectron Spectroscopy (XPS) data and microstructure investigation of polypropylene chains based on the deconvolution of the molecular weight distribution curves by multiple Flory most probable distributions using Gel Permeation Chromatography (GPC) method. The number and relative intensities of these peaks were found correlated to the distribution of multiple active sites. In this investigation, four individual categories of active sites were identified, each of which yields polypropylene with unique properties of molecular weight and chain structure different from other active sites. The reason of the multiplicity of active sites was determined by the presence of different locations of surface titanium species coordinated with other surface atoms or molecules. These different surface complexes of active species determine the multiple active site nature of catalyst which replicates the microtacticity, molecular weight and chain microstructure distribution of polymer. Keywords: Ziegler-Natta catalyst; Multiple active sites; Flory components; Computer simulation; Deconvolution; MWD. DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9596 BJSIR 2011; 46(4): 487-494

scholarly journals 1,1′,3,3′-Tetramesitylquinobis(imidazole)-2,2′-dithione

IUCrData ◽  
2019 ◽  
Vol 4 (9) ◽  
Author(s):  
Jayaraman Selvakumar ◽  
Kuppuswamy Arumugam
Keyword(s):  
Crystal Structure ◽  
Molecular Weight ◽  
Solid State ◽  
Structural Analysis ◽  
Hydrogen Bonds ◽  
Cell Volume ◽  
Title Compound ◽  
Unit Cell Volume ◽  
Density Peaks ◽  
Solvent Molecules

The solid-state structural analysis of the title compound [systematic name: 5,11-disulfanylidene-4,6,10,12-tetrakis(2,4,6-trimethylphenyl)-4,6,10,12-tetraazatricyclo[7.3.0.03,7]dodeca-1(9),3(7)-diene-2,8-dione], C44H44N4O2S2 [+solvent], reveals that the molecule crystallizes in a highly symmetric cubic space group so that one quarter of the molecule is crystallographically unique, the molecule lying on special positions (two mirror planes, two twofold axes and a center of inversion). The crystal structure exhibits large cavities of 193 Å3 accounting for 7.3% of the total unit-cell volume. These cavities contain residual density peaks but it was not possible to unambiguously identify the solvent therein. The contribution of the disordered solvent molecules to the scattering was removed using a solvent mask and is not included in the reported molecular weight. No classical hydrogen bonds are observed between the main molecules.

Modelling of interactions in solutions: alkali halides in DMSO

1979 ◽  
Vol 57 (5) ◽  
pp. 538-551 ◽  
Author(s):  
Peeter Kruus ◽  
Barbara E. Poppe
Keyword(s):  
Reasonable Agreement ◽  
Minimum Energy ◽  
Alkali Halides ◽  
Ion Pair ◽  
Point Of View ◽  
Ion Solvation ◽  
Solvation Energies ◽  
Solvent Molecules ◽  
A Charge ◽  
Energy Configurations

A model of solutions of alkali halides in DMSO is developed. Each ion is described by a radius, a charge, a polarizability, and an exponential repulsion parameter. Each molecule is described by a polarizability, charges, 6-12 energy parameters, and 6-12 distance parameters centered on each of the 10 atoms in the molecule. The model is applied to calculate (i) the vaporization energy of solvent molecules, (ii) single ion solvation energies and configurations of the solvating molecules, and (iii) the energy as a function of reaction coordinate for the formation of an ion pair. The energies and configurations are obtained by allowing the systems to relax to minimum energy configurations by allowing motion of the molecules. The results of (i) give a vaporization energy 60% of the experimental. The results of (ii) give solvation energies in reasonable agreement with the experimental, and configurations which are reasonable from the point of view of mobilities of ions. The results of (iii) show the presence of a distinct solvent separated ion pair which actually has an energy lower than the contact ion pair. Advantages and problems involved in using this approach to model solutions are discussed.

scholarly journals Synthesis of Phosphorus-Containing Polyanilines by Electrochemical Copolymerization

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1029 ◽  
Author(s):  
Beatriz Martínez-Sánchez ◽  
Andrés Felipe Quintero-Jaime ◽  
Francisco Huerta ◽  
Diego Cazorla-Amorós ◽  
Emilia Morallón
Keyword(s):  
Photoelectron Spectroscopy ◽  
Polymeric Materials ◽  
Electroactive Polymers ◽  
Hydrogen Electrode ◽  
X Ray ◽  
Electrochemical Copolymerization ◽  
Phosphorus Containing ◽  
Redox Transitions ◽  
Acid Stable

In this study, the phosphonation of a polyaniline (PANI) backbone was achieved in an acid medium by electrochemical methods using aminophenylphosphonic (APPA) monomers. This was done through the electrochemical copolymerization of aniline with either 2- or 4-aminophenylphosphonic acid. Stable, electroactive polymers were obtained after the oxidation of the monomers up to 1.35 V (reversible hydrogen electrode, RHE). X-ray photoelectron spectroscopy (XPS) results revealed that the position of the phosphonic group in the aromatic ring of the monomer affected the amount of phosphorus incorporated into the copolymer. In addition, the redox transitions of the copolymers were examined by in situ Fourier-transform infrared (FTIR) spectroscopy, and it was concluded that their electroactive structures were analogous to those of PANI. From the APPA monomers it was possible to synthesize, in a controlled manner, polymeric materials with significant amounts of phosphorus in their structure through copolymerization with PANI.

IV. The Micellar Theory of the Structure of Rubber

1942 ◽  
Vol 15 (3) ◽  
pp. 446-451
Author(s):  
G. Gee
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Infinite Dilution ◽  
Mechanical Deformation ◽  
Point Of View ◽  
Pressure Measurements ◽  
Physical Behavior ◽  
Molecular Weights ◽  
Micelle Size ◽  
Weight Data

Abstract The molecular weight data reported in Part II depend on the assumption that the values obtained by extrapolating osmotic pressure measurements to infinite dilution represent true molecular weights. This point of view has been strongly criticized, particularly by Pummerer and his coworkers, according to whom rubber normally exists in solution in the form of micelles comprising more or less well-defined aggregates containing a considerable number of chemical molecules. The- osmotic “molecular weight” is then regarded as the weight of an average micelle. If they exist, these micelles may be important in determining both the chemical and physical behavior of rubber, for we should clearly expect the bonds by which the chemical molecules are bound into micelles to be weaker than those within the molecules. It may be noted that it has been shown elsewhere that the physical properties of a series of rubber fractions are closely related to their osmotic and viscosity molecular weights. Since, according to the micellar theory, these fractions can differ only in micelle size, their mechanical behavior must, from this viewpoint, be determined by the size of the micelles, which must therefore remain intact during mechanical deformation of the rubber. It is the object of the present paper to examine in more detail the basis of the micellar theory, and especially to offer an interpretation of the results of the East method, on which Pummerer's arguments are mainly based.

Polyetherimides—synthesis and structure-property relationships

1993 ◽  
Vol 5 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Martin Davies ◽  
John N Hay ◽  
Barry Woodfine
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Thermal Properties ◽  
Structure Property ◽  
Polymer Molecular Weight ◽  
Chain Flexibility ◽  
Structure Property Relationships ◽  
Polymer Properties ◽  
Synthetic Routes ◽  
Rotational Freedom

Polyetherimides have been synthesized by two complementary routes starting from 4-halophthalic anhydride. A range of polymers has been prepared by varying the structure of the diamines and bisphenols employed in the syntheses. These polymers have been characterized by their m spectra, molecular weight and thermal properties. The applicability and limitations of the synthetic routes are discussed. Structure-property (glass transition temperature, Tg relationships are elucidated and discused in terms of the structural fragments in the polymer chain. Chain flexibility, rotational freedom and inter-chain interactions are all important parameters affecting the polymer properties. The effect of polymer molecular weight on Tg is also discussed.

Electrochemical and XPS Studies of Benzalkonium Chloride for Carbon Steel Protection in Hydrochloric Acid

2017 ◽  
Vol 888 ◽  
pp. 382-388
Author(s):  
Mohd Nazri Idris ◽  
Abdul Razak Daud ◽  
Norinsan Kamil Othman
Keyword(s):  
Carbon Steel ◽  
Potentiodynamic Polarization ◽  
Photoelectron Spectroscopy ◽  
Benzalkonium Chloride ◽  
Adsorption Mechanism ◽  
Point Of View ◽  
Polarization Method ◽  
Corrosion Reaction ◽  
Carbon Steel Surface ◽  
Steel Protection

The efficiency of benzalkonium chloride (BKC) to inhibit the corrosion of carbon steel API 5L in 1 M HCl has been studied by potentiodynamic polarization method and X-ray photoelectron spectroscopy (XPS). Potentiodynamic polarization indicated that BKC is able to retard the corrosion reaction of carbon steel and its corrosion rate decreased with the increasing of BKC concentration up to optimum concentration 7.5 mM. Adsorption and thermodynamic studies indicated that BKC molecules were capable of adsorbing onto carbon steel surface by following Langmuir adsorption isotherm model and their Gibbs free energy obtained at 25, 40, 55 and 70°C were -29.15, -31.67, -37.46 and -35.76 kJ/mol, respectively. Thermodynamically point of view shown that adsorption mechanism of BKC onto carbon steel occurred via both physisorption and chemisorption process. While, adsorption mechanism establish by XPS analysis indicated that BKC was dominantly inhibit the carbon steel via physisorption process. As a conclusion, both potentiodynamic polarization method and XPS suggested that BKC is able to adsorb onto carbon steel and protect the surface from actively react with HCl.

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