Search

Your search keyword '"Blinco, James"' showing total 396 results
Start Over Author "Blinco, James"
396 results on '"Blinco, James"'

105. Folding polymer chains with visible light.

Author

Bastian, Simon, Heiler, Carolin, Lederhose, Paul, Blinco, James P., Blasco, Eva, and Barner-Kowollik, Christopher

Subjects
POLYMERIC nanocomposites, VISIBLE spectra, RING formation (Chemistry)
Abstract

We introduce a mild and efficient avenue to induce the folding of single chain polymer nanoparticles (SCNPs) using visible light. The versatility of the method is based on three folding mechanisms exploiting tetrazole chemistry, i.e., nitrile imine-mediated tetrazole-ene cycloaddition (NITEC), nitrile imine carboxylic acid ligation (NICAL) as well as nitrile imine self-dimerization. To our knowledge, this visible light driven approach is the to-date mildest avenue to fold single polymer chains into compact particles using light. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

107. Exploiting λ‐Orthogonal Photoligation for Layered Surface Patterning.

Author

Lederhose, Paul, Blinco, James P., Barner‐Kowollik, Christopher, Abt, Doris, Welle, Alexander, and Müller, Rouven

Subjects
*CHEMICAL reagents, *SPECTROMETERS, *CHROMATOGRAPHIC analysis, *LIGHT emitting diodes, *TEMPERATURE
Abstract

Abstract: We exploit λ‐orthogonal photoligation of nitrile imine‐mediated tetrazole‐ene cycloaddition (NITEC) chemistry to generate complex, interconnected surface modifications via a simple layered surface patterning approach. By judicious choice of activating chromophores, we introduce a one pot reaction where nitrile imine formation can be triggered independently of other tetrazoles present. When irradiated with visible light, a tetrazole bearing a pyrene chromophore undergoes quantitative elimination of nitrogen to release nitrile imine (which subsequently undergoes trapping with a dipolarophile in a 1,3 dipolar cycloaddition) whereas a tetrazole bearing a phenyl moiety remains unreacted. Subsequent irradiation of the solution with UV light yields the N‐phenyl containing nitrile imine quantitatively, while the pyrene pyrazoline adduct remains unchanged. This λ‐orthogonal photoligation was subsequently exploited for the generation of layered patterned surfaces. Specifically, the visible light active tetrazole was grafted to a silicon wafer and subsequently photolithographically patterned with a dipolarophile modified with a UV‐active tetrazole. Various electron deficient olefins were then patterned in a spatially resolved manner relying on different light activation. The desired functionality was successfully imaged on the silicon wafers using time‐of‐flight–secondary ion mass spectrometry (ToF‐SIMS), demonstrating that a powerful mask‐less lithographic platform technology has been established. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

108. Polymer networks based on photo-caged diene dimerizationElectronic supplementary information (ESI) available: Experimental details and characterization. See DOI: 10.1039/c8mh00951a

Author

KrappitzThese authors contributed equally to this work., Tim, Feist, Florian, Lamparth, Iris, Moszner, Norbert, John, Hendrik, Blinco, James P., Dargaville, Tim R., and Barner-Kowollik, Christopher

Abstract

A powerful, simple and efficient method for photochemical crosslinking, exploiting the self-dimerization of photo-caged dienes based on o-methylbenzaldehydes (o-MBAs) is introduced. Using a small molecule model system it is possible to identify the intermediate and final products of this light induced dimerization process. The bi-functional photocurable monomers contain o-MBA as well as vinylic units, which enables radical copolymerization with other monomers to tune the mechanical properties of the resulting networks. Crosslinked materials with reduced E-moduli ranging from 0.29 to 5.76 GPa and a hardness between 52 and 329 MPa were obtained, thus spanning a wide regime of different ‘soft’ to ‘hard’ material properties. The functional groups can be addressed through simultaneous reaction or in a λ-orthogonal fashion. This orthogonality can be achieved by inducing the free radical polymerization independently of the dimerization either thermally or viaphotoinitiation at a wavelength higher than the wavelength used for the non-radical dimerization process (>400 nm). Critically, this allows for a spatially defined adjustment of both the E-modulus and hardness within the respective material by controlling the irradiation parameters, such as wavelength, curing time and intensity. The introduced self-dimerizing resists thus represent a highly controllable combined radical/non-radical and λ-orthogonal curing system.

Published
2019
Full Text
View/download PDF

120. Spin-coated carbon

Author

Blinco, James P., primary, Chalmers, Benjamin A., additional, Chou, Alison, additional, Fairfull-Smith, Kathryn E., additional, and Bottle, Steven E., additional

Published
2013
Full Text
View/download PDF

149. The evaluation of new and isotopically labeled isoindoline nitroxides and an azaphenalene nitroxide for EPR oximetry

Author

Khan, Nadeem, Blinco, James P., Bottle, Steven E., Hosokawa, Kazuyuki, Swartz, Harold M., and Micallef, Aaron S.

Subjects
*ISOINDOLE, *ELECTRON paramagnetic resonance, *NITROXIDES, *PIPERAZINE, *OXIMETRY, *BIOLOGICAL systems, *CELL-mediated cytotoxicity, *RADIOLABELING
Abstract

Abstract: Isoindoline nitroxides are potentially useful probes for viable biological systems, exhibiting low cytotoxicity, moderate rates of biological reduction and favorable Electron Paramagnetic Resonance (EPR) characteristics. We have evaluated the anionic (5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl; CTMIO), cationic (5-(N,N,N-trimethylammonio)-1,1,3,3-tetramethylisoindolin-2-yloxyl iodide, QATMIO) and neutral (1,1,3,3-tetramethylisoindolin-2-yloxyl; TMIO) nitroxides and their isotopically labeled analogs (2H12- and/or 2H12–15N-labeled) as potential EPR oximetry probes. An active ester analogue of CTMIO, designed to localize intracellularly, and the azaphenalene nitroxide 1,1,3,3-tetramethyl-2,3-dihydro-2-azaphenalen-2-yloxyl (TMAO) were also studied. While the EPR spectra of the unlabeled nitroxides exhibit high sensitivity to O2 concentration, deuteration resulted in a loss of superhyperfine features and a subsequent reduction in O2 sensitivity. Labeling the nitroxides with 15N increased the signal intensity and this may be useful in decreasing the detection limits for in vivo measurements. The active ester nitroxide showed approximately 6% intracellular localization and low cytotoxicity. The EPR spectra of TMAO nitroxide indicated an increased rigidity in the nitroxide ring, due to dibenzo-annulation. [Copyright &y& Elsevier]

Published
2011
Full Text
View/download PDF

150. Investigation of polypropylene degradation during melt processing using a profluorescent nitroxide probe: A laboratory-scale study

Author

Moghaddam, Laleh, Blinco, James P., Colwell, John M., Halley, Peter J., Bottle, Steven E., Fredericks, Peter M., and George, Graeme A.

Subjects
*POLYPROPYLENE, *NITROXIDES, *FLUORESCENCE, *EMISSIONS (Air pollution), *DETECTORS, *VISCOSITY, *SCISSION (Chemistry)
Abstract

Abstract: Degradation of polypropylene (PP) during melt processing was studied using a novel profluorescence technique. The profluorescent nitroxide probe, 1,1,3,3-tetramethyldibenzo[e,g]isoindolin-2-yloxyl (TMDBIO) was added to PP during melt processing to act as a sensor for carbon-centred radicals. Trapping of carbon-centred radicals, formed during degradation of PP, led to an increase in fluorescence emission from TMDBIO adducts. Through analysis of viscosity changes during processing cumulative chain scission degradation was estimated. At processing temperatures of 210°C or below, fluorescence emission from TMDBIO adducts could be correlated with cumulative chain scissions when the number of chain scissions was small. At higher temperatures, a correlation was not observed most probably due to radical-trap instability rather than decomposition of the TMDBIO. Thus, TMDBIO may be used as a profluorescent sensor for degradation of PP during melt processing when the processing temperature is 210°C or below. [Copyright &y& Elsevier]

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results