A5007021045- Molecular Sensors and Ion Detection
- Advanced Polymer Synthesis and Characterization
- Supramolecular Chemistry and Complexes
- Analytical Chemistry and Sensors
- Polymer Nanocomposites and Properties
- Material Dynamics and Properties
- Polymer Surface Interaction Studies
- Polymer composites and self-healing
- Crystallography and molecular interactions
- Corrosion Behavior and Inhibition
- NMR spectroscopy and applications
- Lanthanide and Transition Metal Complexes
- Material Properties and Processing
- Surfactants and Colloidal Systems
- Advanced Chemical Sensor Technologies
- Photonic Crystals and Applications
- Force Microscopy Techniques and Applications
- Electrochemical Analysis and Applications
- Synthesis and properties of polymers
- Synthesis and Reactivity of Heterocycles
- Electrostatics and Colloid Interactions
- Antimicrobial agents and applications
- Adsorption, diffusion, and thermodynamic properties of materials
- Nonlinear Optical Materials Studies
- Epoxy Resin Curing Processes
DSM (Netherlands)
2005-2020
Coventry University
1998-2002
Wageningen University & Research
2000
University of Twente
1996
First the cation, then anion. This describes complexation of alkali metal halides with bifunctional receptors like that on right (R = n-octyl) based calix[4]arenes. The uncomplexed ligand has a strong intramolecular hydrogen bond between urea moieties, which is disrupted by conformational change induced Na+ ion. Only an anion Cl− bound in upper portion calixarene.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUrea-Derivatized p-tert-Butylcalix[4]arenes: Neutral Ligands for Selective Anion ComplexationJurgen Scheerder, Mariacristina Fochi, Johan F. J. Engbersen, and David N. ReinhoudtCite this: Org. Chem. 1994, 59, 25, 7815–7820Publication Date (Print):December 1, 1994Publication History Published online1 May 2002Published inissue 1 December 1994https://pubs.acs.org/doi/10.1021/jo00104a044https://doi.org/10.1021/jo00104a044research-articleACS...
High quality opal-like photonic crystals containing graphene are fabricated using evaporation-driven self-assembly of soft polymer colloids. A miniscule amount pristine within a colloidal crystal lattice results in the formation with strong angle-dependent structural color and stop band that can be reversibly shifted across visible spectrum. The mechanically deformed or change as function their temperature, hence sensitive mechanochromic thermochromic response make them attractive candidates...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComplexation of Halide Anions and Tricarboxylate by Neutral Urea-Derivatized p-tert-Butylcalix[6]arenesJurgen Scheerder, Johan F. J. Engbersen, Alessandro Casnati, Rocco Ungaro, David N. ReinhoudtCite this: Org. Chem. 1995, 60, 20, 6448–6454Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published inissue 1 October...
Calix[4]arenes at the upper rim substituted with two (thio)urea moieties, 2a−c and 4, or acetamido groups, 5, adopt a pinched cone conformation in CDCl3 solution. The is result of diametrical, intramolecular hydrogen bonds was studied by 1H NMR dilution variable-temperature experiments, NOESY spectroscopy, FTIR experiments. these novel calix[4]arenes stable C2D2Cl4 up to least 120 °C. bis(ureido)calix[4]arenes 2b,c give hydrogen-bonded dimer conformation.
The conventional method for synthesizing waterborne polymer colloids is emulsion polymerization using surfactants. An emerging the use of secondary dispersions (SD) polymers in water, which avoids addition any surfactant. Although there are numerous studies water barrier properties (sorption, diffusion, and permeability) (Em) coatings, SD comparison, have not been thoroughly investigated. Here, dynamic vapor sorption analysis used to compare equilibrium isotherms two forms styrene-acrylate...
ABSTRACT The loss of optical transparency when polymer films are immersed in water, which is called “water whitening,” severely limits their use as clear barrier coatings. It found that this problem particularly acute deposited from polymers synthesized via emulsion polymerization using surfactants. Water whitening less severe secondary dispersion (SD) polymers, made by dispersing solution water without the NMR relaxometry combination with transmission analysis and electron microscopy reveal...
The film formation of acrylic latex dispersions, containing different amounts carboxylic acid functional groups by the incorporation methacrylic (MAA), was studied with GARField 1H NMR at various relative humidities (RH). Polymer particles glass-transition temperatures in range from 26 to 50 °C formed films room temperature because hydroplasticization. It found that an increased drying rate due lower RH, evaporation flux water limited polymer. Only second stage this phenomenon more obvious...
The transport of particles within thin, porous media is a complex process which received growing attention due to its applications in filtration, printing and microfluidics devices. effect on liquid imbibition particle clogging can reduce the performance lifetime these applications. However, processes are still not clearly understood challenging investigate. goal this study increase our understanding about concentration thin fibrous membrane filters. In study, an Ultra-Fast Imaging NMR...
Erst das Kation, dann Anion . So verläuft die Komplexierung von Alkalimetallhalogeniden mit Calix[4]arenen (im Bild rechts, R = n ‐Octyl). Der freie Ligand weist im oberen Bereich eine H‐Brücke zwischen den Harnstoff‐Einheiten auf, erst gebrochen wird, wenn sich durch Na + ‐Ionen Konformation des Rezeptors ändert. Danach findet auch Cl − ‐Ion Platz. magnified image
Soft polymer colloidal water suspensions are extremely important formulations for industrial applications such as water-based environmental-friendly coatings, paints, and adhesives. Homogeneity of the final coating at micrometer nanoscale is a crucial factor optimal performance, barrier properties against solvent permeation. Here, we investigated remnant nanostructure in slot-die-coated micrometer-sized thick clear films (clearcoats) three different waterborne colloids (pure soft, pure hard,...
ABSTRACT Waterborne polymer dispersions are widely used in coatings and graphic arts markets as environmentally friendly more sustainable alternatives to solvent borne binders. Traditionally, waterborne (meth)acrylic prepared by emulsion polymerization using low molar mass surfactants a key ingredient control particle size. However, these can have negative influence on the performance of such reduced water resistance adhesion. To mitigate effects surfactants, latexes been developed that...
GARField 1H NMR relaxometry experiments were done to study the drying process of two latices with different polymer Tg and elucidate water mobility behavior during this process. It was found that hard type latex, a above room temperature, dries faster than soft below temperature. Diffusion measurements by means echo time variations at moments in show auto-diffusion decreases increasing solid content latex independent particle Tg. Two pools protons mobilities observed based on transversal...
The transport of nanoparticles in porous media has received growing attention the last decades due to environmental concerns in, for example, printing industry, filtration, and pollutants. Experimental studies on imbibition particle dispersions with sufficiently high spatial temporal resolution are still challenging. This study shows how Ultra-Fast Imaging (UFI) NMR is an ideal tool studying Fe3O4-latex particles penetration a 15 ms 18 μm. In first part, it shown that calibration curve...
A new class of side-chain liquid crystalline polymers with polymethacrylate or polyether backbones and two different mesogenic moieties in one side-chain, i.e. a biphenyl group cholesterol group, have been synthesized. The thermotropic behavior both, the monomeric precursors polymers, has investigated. monomers exhibit smectic chiral nematic phases mesophases. For isotropization temperatures corresponding dimensionless entropy changes ΔS/R depend on parity spacer between mesogens....