LIVIVO - Search results -

Search results

Result 1 - 10 of total 21

Search options

Article ; Online: Visible light induced RAFT for asymmetric functionalization of silica mesopores.

Förster, Claire / Veith, Lothar / Andrieu-Brunsen, Annette

RSC advances

2022 Volume 12, Issue 42, Page(s) 27109–27113

Abstract: One key feature for bioinspired transport design through nanoscale pores is nanolocal, asymmetric as well as multifunctional nanopore functionalization. Here, we use a visible-light induced, controlled photo electron/energy transfer-reversible addition- ... ...

Abstract	One key feature for bioinspired transport design through nanoscale pores is nanolocal, asymmetric as well as multifunctional nanopore functionalization. Here, we use a visible-light induced, controlled photo electron/energy transfer-reversible addition-fragmentation chain-transfer (PET-RAFT) polymerization for asymmetric polymer placement into mesoporous silica thin films including asymmetric polymer sequence design.
Language	English
Publishing date	2022-09-23
Publishing country	England
Document type	Journal Article
ISSN	2046-2069
ISSN (online)	2046-2069
DOI	10.1039/d2ra05422a
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online ; Thesis: Optimization and application of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) for the detection of nanomaterials in tissue thin sections

Veith, Lothar [Verfasser]

2019

Author's details	Lothar Veith
Keywords	Medizin, Gesundheit ; Medicine, Health
Subject code	sg610
Language	English
Publisher	Universitätsbibliothek der Universität Siegen
Publishing place	Siegen
Document type	Book ; Online ; Thesis
Database	Digital theses on the web

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article: Ionic Conductivity of a Solid Polymer Electrolyte Confined in Nanopores

Tu, Chien-Hua / Veith, Lothar / Butt, Hans-Jürgen / Floudas, George

Macromolecules. 2022 Feb. 07, v. 55, no. 4

2022

Abstract: Using in situ nanodielectric spectroscopy, we investigate if and how the ionic conductivity of the archetypal polymer electrolyte poly(ethylene oxide)/lithium bis(trifluoromethane sulfone)imide (PEO/LiTFSI) is affected during and after imbibition in ... ...

Abstract	Using in situ nanodielectric spectroscopy, we investigate if and how the ionic conductivity of the archetypal polymer electrolyte poly(ethylene oxide)/lithium bis(trifluoromethane sulfone)imide (PEO/LiTFSI) is affected during and after imbibition in nanopores. We identify two distinct stages of imbibition. In the first stage, up to the complete pore filling, ion conductivity increased above the bulk value. In the second stage, after imbibition, ion conductivity decreased following a stretched exponential dependence. Time-of-flight secondary ion mass spectroscopy revealed a uniform distribution of Li⁺ and TFSI– ions in the templates. The timescale of conductivity reduction was very long. For a given molar mass, the characteristic times strongly depend on the ratio 2Rg/D where Rg is the radius of gyration and D is the pore diameter. For a given pore diameter, the characteristic times were some 9 orders of magnitude slower than the PEO terminal relaxation and more than 11 orders of magnitude slower than the segmental relaxation. The reduced ionic conductivity is explained by the adsorption of polymer segments on the pore walls. Polymer adsorption inevitably affects ion dynamics by (i) increasing the glass temperature and (ii) reducing the number of mobile ions. The molar mass dependence of the characteristic adsorption times (τₐdₛ ≈ N²) was in agreement with a scaling theory proposed by de Gennes. Possible consequences of the current study to energy conversion are discussed.
Keywords	adsorption ; energy conversion ; glass ; imbibition ; mass spectrometry ; molecular weight ; nanopores ; temperature
Language	English
Dates of publication	2022-0207
Size	p. 1332-1341.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1491942-4
ISSN	1520-5835 ; 0024-9297
ISSN (online)	1520-5835
ISSN	0024-9297
DOI	10.1021/acs.macromol.1c02490
Database	NAL-Catalogue (AGRICOLA)

Order via subito

Article ; Online: Room-Temperature Halide Perovskite Field-Effect Transistors by Ion Transport Mitigation.

Jeong, Beomjin / Veith, Lothar / Smolders, Thijs J A M / Wolf, Matthew J / Asadi, Kamal

Advanced materials (Deerfield Beach, Fla.)

2021 Volume 33, Issue 39, Page(s) e2100486

Abstract: Solution-processed halide perovskites have emerged as excellent optoelectronic materials for applications in photovoltaic solar cells and light-emitting diodes. However, the presence of mobile ions in the material hinders the development of perovskite ... ...

Abstract	Solution-processed halide perovskites have emerged as excellent optoelectronic materials for applications in photovoltaic solar cells and light-emitting diodes. However, the presence of mobile ions in the material hinders the development of perovskite field-effect transistors (FETs) due to screening of the gate potential in the nearby perovskite channel, and the resulting impediment to achieving gate modulation of an electronic current at room temperature. Here, room-temperature operation is demonstrated in cesium lead tribromide (CsPbBr
Language	English
Publishing date	2021-08-13
Publishing country	Germany
Document type	Journal Article
ZDB-ID	1474949-X
ISSN	1521-4095 ; 0935-9648
ISSN (online)	1521-4095
ISSN	0935-9648
DOI	10.1002/adma.202100486
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

Order via subito

Details ▾
- Full text online
- Order with fees

Article ; Online: Tuning the Charge of Sliding Water Drops.

Wong, William S Y / Bista, Pravash / Li, Xiaomei / Veith, Lothar / Sharifi-Aghili, Azadeh / Weber, Stefan A L / Butt, Hans-Jürgen

Langmuir : the ACS journal of surfaces and colloids

2022 Volume 38, Issue 19, Page(s) 6224–6230

Abstract: When a water drop slides over a hydrophobic surface, it usually acquires a positive charge and deposits the negative countercharge on the surface. Although the electrification of solid surfaces induced after contact with a liquid is intensively studied, ... ...

Abstract	When a water drop slides over a hydrophobic surface, it usually acquires a positive charge and deposits the negative countercharge on the surface. Although the electrification of solid surfaces induced after contact with a liquid is intensively studied, the actual mechanisms of charge separation, so-termed slide electrification, are still unclear. Here, slide electrification is studied by measuring the charge of a series of water drops sliding down inclined glass plates. The glass was coated with hydrophobic (hydrocarbon/fluorocarbon) and amine-terminated silanes. On hydrophobic surfaces, drops charge positively while the surfaces charge negatively. Hydrophobic surfaces coated with a mono-amine (3-aminopropyltriethyoxysilane) lead to negatively charged drops and positively charged surfaces. When coated with a multiamine (
Language	English
Publishing date	2022-05-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	2005937-1
ISSN	1520-5827 ; 0743-7463
ISSN (online)	1520-5827
ISSN	0743-7463
DOI	10.1021/acs.langmuir.2c00941
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article: New methodical approaches for the investigation of weathered epoxy resins used for corrosion protection of steel constructions

Brand, Simon / Veith, Lothar / Baier, Roland / Dietrich, Christian / Schmid, Matthias J / Ternes, Thomas A

Journal of hazardous materials. 2020 Aug. 05, v. 395

2020

Abstract: Epoxy resin coatings applied to steel constructions for corrosion protection purposes are often exposed to UV-irradiation and weathering during the construction process. Chemical alteration of the hardened coating might lead to i) the release of ... ...

Abstract	Epoxy resin coatings applied to steel constructions for corrosion protection purposes are often exposed to UV-irradiation and weathering during the construction process. Chemical alteration of the hardened coating might lead to i) the release of potentially harmful substances into the environment and ii) delamination of the polyurethane top layer. However, chemical processes and mechanisms occurring on the surfaces of exposed epoxy resin coatings are not fully understood yet. Herein, we present an innovative approach combining time-of-flight secondary ion mass spectrometry (ToF-SIMS) with inductively coupled plasma mass spectrometry (ICP-MS) and liquid chromatography mass spectrometry (LC-MS) enabling the elucidation of underlying chemical processes and the identification of released organic and inorganic photolytic products. IR-spectroscopy and experiments targeting the acidity/pH-value changes on top of weathered surfaces complement our investigations. It was confirmed that UV-A irradiation leads to photooxidative degradation of the epoxy resin and that inorganic photolytic products are exposed on the weathered surfaces. Polar moieties (hydroxyls, carbonyls, carboxyls, amines) and released metalloids form a hydrophilic surface layer, which hinders adhesion and eventually prevents profound chemical linkage of the polyurethane top layer. Thus, an early delamination of the top layer might occur very likely.
Keywords	acidity ; adhesion ; amines ; atomic absorption spectrometry ; coatings ; corrosion ; delamination ; epoxides ; hydrophilicity ; infrared spectroscopy ; irradiation ; liquid chromatography ; mass spectrometry ; metalloids ; moieties ; photooxidation ; polyurethanes ; resins ; steel ; ultraviolet radiation ; weathering
Language	English
Dates of publication	2020-0805
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1491302-1
ISSN	1873-3336 ; 0304-3894
ISSN (online)	1873-3336
ISSN	0304-3894
DOI	10.1016/j.jhazmat.2020.122289
Database	NAL-Catalogue (AGRICOLA)

Order via subito

Article: Organic Versus Inorganic Supports for Metallocenes: The Influence of Rigidity on the Homogeneity of the Polyolefin Microstructure and Properties

Hejazi-Dehaghani, Zahra-Alsadat / Arabi, Hassan / Thalheim, Daniel / Vidakovic, Danijel / Nekoomanesh Haghighi, Mehdi / Veith, Lothar / Klapper, Markus

Macromolecules. 2021 Feb. 01, v. 54, no. 6

2021

Abstract: A procedure to obtain very uniform polyolefin copolymers by supported metallocenes is presented. Conventional metallocene or Ziegler–Natta catalysts, both immobilized on inorganic supports, yield only copolymers with inhomogeneous comonomer incorporation ...

Abstract	A procedure to obtain very uniform polyolefin copolymers by supported metallocenes is presented. Conventional metallocene or Ziegler–Natta catalysts, both immobilized on inorganic supports, yield only copolymers with inhomogeneous comonomer incorporation and broad short-chain branching distribution. The main reasons are diffusional limitations of the monomers or the multisite character of the catalysts. By comparing inorganic and organic supports, we demonstrate that metallocenes immobilized on organic supports solve these problems. In this regard, organic and soft nanosized polystyrene particles (nPS) versus industrially used, hard, and inorganic SiO₂ were used to support [Me₂Si(Ind)₂ZrCl₂/MAO (I) and Me₂Si(Benz[e]-Ind)₂ZrCl₂/MAO (BI)] catalysts for ethylene/1-hexene copolymerization. In the inorganic case, the catalyst systems show a substantial inconsistency in the copolymers’ branching distribution, resulting in phase separation. One phase is hexene-poor with high melting temperature (Tₘ) and high molecular weight (MW). The second, hexene-rich phase, however, shows lower Tₘ and MW. By using organic supports, comonomers are uniformly inserted into the polymer chain and homogeneous microstructured copolymers are obtained. These findings are mainly attributed to diffusion processes of the monomers into the soft organic material. To prove this conclusion and to elucidate the structure of the catalyst system, various characterization techniques such as time-of-flight secondary ion mass spectrometry and scanning electron microscopy–energy-dispersive X-ray were performed.
Keywords	X-radiation ; catalysts ; composite polymers ; copolymerization ; mass spectrometry ; microstructure ; molecular weight ; polyolefin ; polystyrenes ; separation ; temperature
Language	English
Dates of publication	2021-0201
Size	p. 2667-2680.
Publishing place	American Chemical Society
Document type	Article
Note	NAL-AP-2-clean
ZDB-ID	1491942-4
ISSN	1520-5835 ; 0024-9297
ISSN (online)	1520-5835
ISSN	0024-9297
DOI	10.1021/acs.macromol.0c01920
Database	NAL-Catalogue (AGRICOLA)

Order via subito

Article: Tuning the Charge of Sliding Water Drops

Wong, William S. Y. / Bista, Pravash / Li, Xiaomei / Veith, Lothar / Sharifi-Aghili, Azadeh / Weber, Stefan A. L. / Butt, Hans-Jürgen

Langmuir. 2022 May 02, v. 38, no. 19

2022

Abstract	When a water drop slides over a hydrophobic surface, it usually acquires a positive charge and deposits the negative countercharge on the surface. Although the electrification of solid surfaces induced after contact with a liquid is intensively studied, the actual mechanisms of charge separation, so-termed slide electrification, are still unclear. Here, slide electrification is studied by measuring the charge of a series of water drops sliding down inclined glass plates. The glass was coated with hydrophobic (hydrocarbon/fluorocarbon) and amine-terminated silanes. On hydrophobic surfaces, drops charge positively while the surfaces charge negatively. Hydrophobic surfaces coated with a mono-amine (3-aminopropyltriethyoxysilane) lead to negatively charged drops and positively charged surfaces. When coated with a multiamine (N-(3-trimethoxysilylpropyl)diethylenetriamine), a gradual transition from positively to negatively charged drops is observed. We attribute this tunable drop charging to surface-directed ion transfer. Some of the protons accepted by the amine-functionalized surfaces (−NH₂ with H⁺ acceptor) remain on the surface even after drop departure. These findings demonstrate the facile tunability of surface-controlled slide electrification.
Keywords	glass ; liquids ; perfluorocarbons ; silanes
Language	English
Dates of publication	2022-0502
Size	p. 6224-6230.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	2005937-1
ISSN	1520-5827 ; 0743-7463
ISSN (online)	1520-5827
ISSN	0743-7463
DOI	10.1021/acs.langmuir.2c00941
Database	NAL-Catalogue (AGRICOLA)

Order via subito

Article ; Online: New methodical approaches for the investigation of weathered epoxy resins used for corrosion protection of steel constructions.

Brand, Simon / Veith, Lothar / Baier, Roland / Dietrich, Christian / Schmid, Matthias J / Ternes, Thomas A

Journal of hazardous materials

2020 Volume 395, Page(s) 122289

Abstract	Epoxy resin coatings applied to steel constructions for corrosion protection purposes are often exposed to UV-irradiation and weathering during the construction process. Chemical alteration of the hardened coating might lead to i) the release of potentially harmful substances into the environment and ii) delamination of the polyurethane top layer. However, chemical processes and mechanisms occurring on the surfaces of exposed epoxy resin coatings are not fully understood yet. Herein, we present an innovative approach combining time-of-flight secondary ion mass spectrometry (ToF-SIMS) with inductively coupled plasma mass spectrometry (ICP-MS) and liquid chromatography mass spectrometry (LC-MS) enabling the elucidation of underlying chemical processes and the identification of released organic and inorganic photolytic products. IR-spectroscopy and experiments targeting the acidity/pH-value changes on top of weathered surfaces complement our investigations. It was confirmed that UV-A irradiation leads to photooxidative degradation of the epoxy resin and that inorganic photolytic products are exposed on the weathered surfaces. Polar moieties (hydroxyls, carbonyls, carboxyls, amines) and released metalloids form a hydrophilic surface layer, which hinders adhesion and eventually prevents profound chemical linkage of the polyurethane top layer. Thus, an early delamination of the top layer might occur very likely.
Language	English
Publishing date	2020-02-12
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	1491302-1
ISSN	1873-3336 ; 0304-3894
ISSN (online)	1873-3336
ISSN	0304-3894
DOI	10.1016/j.jhazmat.2020.122289
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article: Electropolymerization of Polydopamine at Electrode-Supported Insulating Mesoporous Films.

Varol, H Samet / Herberger, Tilmann / Kirsch, Marius / Mikolei, Joanna / Veith, Lothar / Kannan-Sampathkumar, Venkataprasanna / Brand, Raoul D / Synatschke, Christopher V / Weil, Tanja / Andrieu-Brunsen, Annette

Chemistry of materials : a publication of the American Chemical Society

2023 Volume 35, Issue 21, Page(s) 9192–9207

Abstract: Bioinspired, stimuli-responsive, polymer-functionalized mesoporous films are promising platforms for precisely regulating nanopore transport toward applications in water management, iontronics, catalysis, sensing, drug delivery, or energy conversion. ... ...

Abstract	Bioinspired, stimuli-responsive, polymer-functionalized mesoporous films are promising platforms for precisely regulating nanopore transport toward applications in water management, iontronics, catalysis, sensing, drug delivery, or energy conversion. Nanopore technologies still require new, facile, and effective nanopore functionalization with multi- and stimuli-responsive polymers to reach these complicated application targets. In recent years, zwitterionic and multifunctional polydopamine (PDA) films deposited on planar surfaces by electropolymerization have helped surfaces respond to various external stimuli such as light, temperature, moisture, and pH. However, PDA has not been used to functionalize nanoporous films, where the PDA-coating could locally regulate the ionic nanopore transport. This study investigates the electropolymerization of homogeneous thin PDA films to functionalize nanopores of mesoporous silica films. We investigate the effect of different mesoporous film structures and the number of electropolymerization cycles on the presence of PDA at mesopores and mesoporous film surfaces. Our spectroscopic, microscopic, and electrochemical analysis reveals that the amount and location (pores and surface) of deposited PDA at mesoporous films is related to the combination of the number of electropolymerization cycles and the mesoporous film thickness and pore size. In view of the application of the proposed PDA-functionalized mesoporous films in areas requiring ion transport control, we studied the ion nanopore transport of the films by cyclic voltammetry. We realized that the amount of PDA in the nanopores helps to limit the overall ionic transport, while the pH-dependent transport mechanism of pristine silica films remains unchanged. It was found that (i) the pH-dependent deprotonation of PDA and silica walls and (ii) the insulation of the indium-tin oxide (ITO) surface by increasing the amount of PDA within the mesoporous silica film affect the ionic nanopore transport.
Language	English
Publishing date	2023-11-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	1500399-1
ISSN	1520-5002 ; 0897-4756
ISSN (online)	1520-5002
ISSN	0897-4756
DOI	10.1021/acs.chemmater.3c01890
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

To top

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito