1
|
Wu R, Lenz TM, Alfayez FAS, Zhao R, Rupper P, Perret E, Lehner S, Jovic M, Gaan S, Rieger B, Heuberger M. Ambient Catalytic Spinning of Polyethylene Nanofibers. Angew Chem Int Ed Engl 2024; 63:e202315326. [PMID: 38226704 DOI: 10.1002/anie.202315326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
A novel single-atom Ni(II) catalyst (Ni-OH) is covalently immobilized onto the nano-channels of mesoporous Santa Barbara Amorphous (SBA)-15 particles and isotropic Anodized Aluminum Oxide (AAO) membrane for confined-space ethylene extrusion polymerization. The presence of surface-tethered Ni complexes (Ni@SBA-15 and Ni@AAO) is confirmed by the inductively coupled plasma-optical emission spectrometry (ICP-OES) and X-ray photoelectron spectroscopy (XPS). In the catalytic spinning process, the produced PE materials exhibit very homogeneous fibrous morphology at nanoscale (diameter: ~50 nm). The synthesized PE nanofibers extrude in a highly oriented manner from the nano-reactors at ambient temperature. Remarkably high Mw (1.62×106 g mol-1 ), melting point (124 °C), and crystallinity (41.8 %) are observed among PE samples thanks to the confined-space polymerization. The chain-walking behavior of surface tethered Ni catalysts is greatly limited by the confinement inside the nano-channels, leading to the formation of very low-branched PE materials (13.6/1000 C). Due to fixed supported catalytic topology and room temperature, the filaments are expected to be free of entanglement. This work signifies an important step towards the realization of a continuous mild catalytic-spinning (CATSPIN) process, where the polymer is directly synthesized into fiber shape at negligible chain branching and elegantly avoiding common limitations like thermal degradation or molecular entanglement.
Collapse
Affiliation(s)
- Ruikai Wu
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
- Department of Materials, ETH, Zurich, 8092, Zurich, Switzerland
| | - Tim M Lenz
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Fayez Abdullah S Alfayez
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Ruohan Zhao
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Patrick Rupper
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Edith Perret
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Sandro Lehner
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Milijana Jovic
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Sabyasachi Gaan
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Bernhard Rieger
- WACKER-Chair of Macromolecular Chemistry, Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Manfred Heuberger
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
- Department of Materials, ETH, Zurich, 8092, Zurich, Switzerland
| |
Collapse
|
2
|
Wu R, Klingler Wu W, Stieglitz L, Gaan S, Rieger B, Heuberger M. Recent advances on α-diimine Ni and Pd complexes for catalyzed ethylene (Co)polymerization: A comprehensive review. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
3
|
Wu R, Stieglitz L, Lehner S, Jovic M, Rentsch D, Neels A, Gaan S, Rieger B, Heuberger M. Fluorine and Hydroxyl Containing Unsymmetrical a-Diimine Ni (II) Dichlorides with Improved Catalytic Performance for Ethylene Polymerization. Eur Polym J 2023. [DOI: 10.1016/j.eurpolymj.2023.111830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
4
|
Zhao R, Schmutz P, Jeurgens LPH, Chen J, Gooneie A, Ott N, Gaan S, Heuberger M. Two Steady-State Adsorption Modes of Phosphonic Acids on Aluminum Surfaces. ACS Appl Mater Interfaces 2022; 14:39467-39477. [PMID: 35994435 DOI: 10.1021/acsami.2c07128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The phosphonic acid (PA) surface treatment on various metal substrates is of high industrial relevance, and the PA molecular structure significantly affects its quality. In this work, systematic variation of the PA molecular steric and electron environment helps discern two steady-state adsorption modes on an aluminum surface. The PA molecular structure was varied systematically, which included inorganic phosphorus acid, alkyl phosphonic acids, and phenyl phosphonic acids. To explore their in situ dynamics of adsorption/desorption on the electrochemically unstable aluminum, techniques such as electrochemical impedance spectroscopy and inductively coupled plasma optical emission spectrometry were employed. A range of different types of interfacial layers are formed on the aluminum surface, namely, from the dissolution-limiting physisorbed layer to a quasi-inhibiting chemisorbed layer on the aluminum surface in acidic (pH ≈ 2.2) solution. Presented findings establish the dynamic steady-state nature of this type of interface. They reveal fundamental relationships among adsorbent steric or electronic effects, the steady-state interface morphology, and the steady-state aluminum dissolution rate. The study brings also a more differentiated molecular structure-related description of the aluminum dissolution inhibition of PAs and relates it to molecular density functional theory calculations.
Collapse
Affiliation(s)
- Ruohan Zhao
- Empa, Materials Science and Technology, Advanced Fibers, 9030 St. Gallen, Switzerland
- Empa, Materials Science and Technology, Joining Technologies and Corrosion, 8600 Dübendorf, Switzerland
- ETH Zurich, Department of Materials, 8093 Zürich, Switzerland
| | - Patrik Schmutz
- Empa, Materials Science and Technology, Joining Technologies and Corrosion, 8600 Dübendorf, Switzerland
- ETH Zurich, Department of Materials, 8093 Zürich, Switzerland
| | - Lars P H Jeurgens
- Empa, Materials Science and Technology, Joining Technologies and Corrosion, 8600 Dübendorf, Switzerland
| | - Jiuke Chen
- Empa, Materials Science and Technology, Advanced Fibers, 9030 St. Gallen, Switzerland
- ETH Zurich, Department of Materials, 8093 Zürich, Switzerland
| | - Ali Gooneie
- Empa, Materials Science and Technology, Advanced Fibers, 9030 St. Gallen, Switzerland
- Maastricht University, Department of Circular Chemical Engineering, Chair of Circular Plastics, 6167 RD Geleen, The Netherlands
| | - Noémie Ott
- Empa, Materials Science and Technology, Joining Technologies and Corrosion, 8600 Dübendorf, Switzerland
| | - Sabyasachi Gaan
- Empa, Materials Science and Technology, Advanced Fibers, 9030 St. Gallen, Switzerland
| | - Manfred Heuberger
- Empa, Materials Science and Technology, Advanced Fibers, 9030 St. Gallen, Switzerland
- ETH Zurich, Department of Materials, 8093 Zürich, Switzerland
| |
Collapse
|
5
|
Cai Y, Yang T, Mitrano DM, Heuberger M, Hufenus R, Nowack B. Systematic Study of Microplastic Fiber Release from 12 Different Polyester Textiles during Washing. Environ Sci Technol 2020; 54:4847-4855. [PMID: 32250104 DOI: 10.1021/acs.est.9b07395] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microplastic fibers (MPFs) have been found to be a major form of microplastics in freshwaters, and washing of synthetic textiles has been identified as one of their main sources. The aim of this work was to use a panel of 12 different textiles of representative fibers and textile types to investigate the source(s) of the MPF during washing. Using standardized washing tests, textile swatches tailored using five different cutting/sewing methods were washed up to 10 times. The MPF quantity and fiber length were determined using image analysis. The 12 textiles demonstrated great variability in MPF release, ranging from 210 to 72,000 MPF/g textile per wash. The median MPF length ranged from 165 to 841 μm. The number of released MPF was influenced by the cutting method, where scissor-cut samples released 3-21 times higher numbers of MPF than the laser-cut samples. The textiles with mechanically processed surfaces (i.e., fleece) released significantly more (p-value < 0.001) than the textiles with unprocessed surfaces. For all textiles, the MPF release decreased with repeated wash cycles, and a small continuous fiber release was observed after 5-6 washings, accompanied by a slight increase in the fiber length. The decrease in the number of MPF released is likely caused by depletion of the production-inherited MPFs trapped within the threads or the textile structure. The comparison of MPF release from laser-cut samples, which had sealed edges, and the other cutting methods allowed us to separate the contributions of the edge- and surface-sourced fibers from the textiles to the total release. On an average, 84% (range 49-95%) of the MPF release originated from the edges, highlighting the importance of the edge-to-surface ratio when comparing different release studies. The large contribution of the edges to the total release offers options for technical solutions which have the possibility to control MPF formation throughout the textile manufacturing chain by using cutting methods which minimize MPF formation.
Collapse
Affiliation(s)
- Yaping Cai
- Technology and Society Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 901 St. Gallen, Switzerland
| | - Tong Yang
- Technology and Society Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 901 St. Gallen, Switzerland
| | - Denise M Mitrano
- Process Engineering Department, Eawag-Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Manfred Heuberger
- Laboratory for Advanced Fibers, Empa-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Rudolf Hufenus
- Laboratory for Advanced Fibers, Empa-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Bernd Nowack
- Technology and Society Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 901 St. Gallen, Switzerland
| |
Collapse
|
6
|
Bülbül E, Hegemann D, Geue T, Heuberger M. How the dynamics of subsurface hydration regulates protein-surface interactions. Colloids Surf B Biointerfaces 2020; 190:110908. [PMID: 32163842 DOI: 10.1016/j.colsurfb.2020.110908] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/13/2020] [Accepted: 02/25/2020] [Indexed: 10/24/2022]
Abstract
The role of water structure near surfaces has been scrutinized extensively because it is accepted to control protein-surface interactions, however, often avoiding effects of hydration dynamics. Relating to this, we have recently discussed how the amount and state of water, accumulated within various hydrophobic-to-hydrophilic subsurface gradients of plasma polymer films, influence the magnitude of adsorbed bovine serum albumin, spurring the hypothesis of the presence of a subsurface dipolar field. This study now analyzes the kinetics of hydration by systematically introducing modified gradient architectures and relating different hydration times to the adsorption of a dipolar probing protein. We find that dry-stored subsurface gradients, owing nominally identical surface characteristics, exhibits comparable surface potential and protein adsorption values, while they behave in a different manner at transient hydration times of few hours, before reaching near-equilibrium state of the hydration. A characteristic hydration time is found where protein adsorption on gradient films is minimal, unveiling the transient nature of the effect. In general, protein adsorption is sensitive to the time allowed for hydration of the adsorbent surface, supporting our initial hypothesis inasmuch as the quantity as well as quality of water inside the subsurface matrix is crucial for controlling protein-surface interactions.
Collapse
Affiliation(s)
- Ezgi Bülbül
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, 9014, St. Gallen, Switzerland; Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
| | - Dirk Hegemann
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, 9014, St. Gallen, Switzerland.
| | - Thomas Geue
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland.
| | - Manfred Heuberger
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, 9014, St. Gallen, Switzerland; Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
| |
Collapse
|
7
|
Arz MI, Kratky T, Günther S, Rodewald K, Burger T, Heuberger M, Rieger B. Sequential immobilization of ansa-hafnocene complexes for propene polymerization. J Organomet Chem 2020. [DOI: 10.1016/j.jorganchem.2019.121075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
8
|
Bülbül E, Rupper P, Geue T, Bernard L, Heuberger M, Hegemann D. Extending the Range of Controlling Protein Adsorption via Subsurface Architecture. ACS Appl Mater Interfaces 2019; 11:42760-42772. [PMID: 31644873 DOI: 10.1021/acsami.9b14584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recently, it has been shown that water, confined in a plasma polymer subsurface chemical gradient, nanometers below the surface, significantly reduced the amount of adsorbed protein bovine serum albumin (BSA). Relating to this effect, we proposed the hypothesis that oriented water molecules within the subsurface gradient generate a long-range dipolar field, which interacts with dipolar proteins such as BSA near the surface region. This study extends the above used in situ multistep plasma deposition process to introduce plasma oxidation modifications of the subsurface architecture with the aim to further control the effect on protein adsorption. Neutron reflectivity measurements reveal that the oxidation time increases the amount of matrix-confined water. There is, however, an optimal oxidation time to obtain minimal protein adsorption, which suggests that a minimal distance between confined water molecules plays an important role. Altogether we can extend the range of controlling the adsorbed protein mass by the introduction of this additional plasma oxidation step.
Collapse
Affiliation(s)
- Ezgi Bülbül
- Laboratory for Advanced Fibers, Empa , Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen , Switzerland
- Laboratory for Surface Science and Technology, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
| | - Patrick Rupper
- Laboratory for Advanced Fibers, Empa , Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen , Switzerland
| | - Thomas Geue
- Laboratory for Neutron Scattering and Imaging , Paul Scherrer Institute , 5232 Villigen PSI , Switzerland
| | - Laetitia Bernard
- Laboratory for Nanoscale Materials Science, Empa , Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland
| | - Manfred Heuberger
- Laboratory for Advanced Fibers, Empa , Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen , Switzerland
- Laboratory for Surface Science and Technology, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
| | - Dirk Hegemann
- Laboratory for Advanced Fibers, Empa , Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen , Switzerland
| |
Collapse
|
9
|
|
10
|
Hegemann D, Hocquard N, Heuberger M. Nanoconfined water can orient and cause long-range dipolar interactions with biomolecules. Sci Rep 2017; 7:17852. [PMID: 29259309 PMCID: PMC5736754 DOI: 10.1038/s41598-017-18258-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/08/2017] [Indexed: 11/25/2022] Open
Abstract
Surface properties are generally determined by the top most surface layer also defining how molecules adsorb onto it. By exploring effects due to interactions with deeper subsurface layers, however, long-range interaction forces were found to also significantly contribute to molecular adsorption, in which hydration of the subsurface region is the key factor. Water molecules confined to a subsurface amphiphilic gradient are confirmed to cause these long-range dipolar interactions by preferential orientation, thus significantly changing the way how a protein interacts with the surface. These findings imply future exploitation of an additional factor to modulate adsorption processes.
Collapse
Affiliation(s)
- Dirk Hegemann
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Advanced Fibers, Lerchenfeldstrasse 5, 9014, St.Gallen, Switzerland.
| | - Nicolas Hocquard
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Advanced Fibers, Lerchenfeldstrasse 5, 9014, St.Gallen, Switzerland
| | - Manfred Heuberger
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Advanced Fibers, Lerchenfeldstrasse 5, 9014, St.Gallen, Switzerland.
| |
Collapse
|
11
|
Rupper P, Vandenbossche M, Bernard L, Hegemann D, Heuberger M. Composition and Stability of Plasma Polymer Films Exhibiting Vertical Chemical Gradients. Langmuir 2017; 33:2340-2352. [PMID: 28195489 DOI: 10.1021/acs.langmuir.6b04600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Controlling the balance between stability and functional group density in grown plasma polymer films is the key to diverse applications such as drug release, tissue-engineered implants, filtration, contact lenses, microfluidics, electrodes, sensors, etc. Highly functional plasma polymer films typically show a limited stability in air or aqueous environments due to mechanisms like molecular reorganization, oxidation, and hydrolysis. Stabilization is achieved by enhancing cross-linking at the cost of the terminal functional groups such as -OH and -COOH, but also -NH2, etc. To overcome such limitations, a structural and chemical gradient was introduced perpendicular to the surface plane; this vertical gradient structure is composed of a highly cross-linked base layer, gradually changing into a more functional nanoscaled surface termination layer. This was achieved using CO2/C2H4 discharges with decreasing power input and increasing gas ratio during plasma polymer deposition. The aging behavior and stability of such oxygen-functional vertical gradient nanostructures were studied in air and in different aqueous environments (acidic pH 4, neutral pH ≈ 6.2, and basic pH 10). Complementary characterization methods were used, including angle-resolved X-ray photoelectron spectroscopy (ARXPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) as well as water contact angle (WCA) measurements. It was found that in air, the vertical gradient films are stabilized over a period of months. The same gradients also appear to be stable in neutral water over a period of at least 1 week. Changes in the oxygen depth profiles have been observed at pH 4 and pH 10 showing structural and chemical aging effects on different time scales. The use of vertical gradient plasma polymer nanofilms thus represents a novel approach providing enhanced stability, thus opening the possibility for new applications.
Collapse
Affiliation(s)
- Patrick Rupper
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Marianne Vandenbossche
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Laetitia Bernard
- Laboratory for Nanoscale Materials Science, Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Dirk Hegemann
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Manfred Heuberger
- Laboratory for Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| |
Collapse
|
12
|
Hegemann D, Lorusso E, Butron-Garcia MI, Blanchard NE, Rupper P, Favia P, Heuberger M, Vandenbossche M. Suppression of Hydrophobic Recovery by Plasma Polymer Films with Vertical Chemical Gradients. Langmuir 2016; 32:651-654. [PMID: 26716609 DOI: 10.1021/acs.langmuir.5b03913] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Vertical chemical gradients extending over a few nanometers were explored. The gradients are based on plasma-polymerized oxygen-containing ethylene (ppOEt) films. Using plasma conditions with low CO2/C2H4 ratio and high energy input, cross-linked films were deposited as base layer, while increasing CO2 and lowering energy input resulted in less cross-linked yet highly functional films as applied as top layer. Aging studies indicate that, in particular, for very thin gradient structures, the cross-linked subsurface zone effectively hinders reorientation of the surface functional groups, thus restricting hydrophobic recovery and oxidation effects.
Collapse
Affiliation(s)
- Dirk Hegemann
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Emanuela Lorusso
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
- Department of Chemistry, University of Bari , Via Orabona 4, 70126 Bari, Italy
| | - Maria-Isabel Butron-Garcia
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Noémi E Blanchard
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Patrick Rupper
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Pietro Favia
- Department of Chemistry, University of Bari , Via Orabona 4, 70126 Bari, Italy
| | - Manfred Heuberger
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Marianne Vandenbossche
- Laboratory of Advanced Fibers, Swiss Federal Laboratories for Materials Science and Technology, Empa , Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| |
Collapse
|
13
|
Schöller K, Toncelli C, Experton J, Widmer S, Rentsch D, Vetushka A, Martin CJ, Heuberger M, Housecroft CE, Constable EC, Boesel LF, Scherer LJ. 2,2′:6′,2′′-Terpyridine-functionalized redox-responsive hydrogels as a platform for multi responsive amphiphilic polymer membranes. RSC Adv 2016. [DOI: 10.1039/c6ra23677d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amphiphilic polymer co-networks were functionalized with spyropiran and terpyridine yielding multi-responsive membranes with switchable properties and potential applications in drug delivery and medical sensors.
Collapse
Affiliation(s)
- Katrin Schöller
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | - Claudio Toncelli
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | - Juliette Experton
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | - Susanne Widmer
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | - Daniel Rentsch
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 8600 Dübendorf
- Switzerland
| | - Aliaksei Vetushka
- Laboratory of Nanostructures and Nanomaterials
- Institute of Physics AS CR
- 162 00 Prague 6
- Czech Republic
| | - Colin J. Martin
- Department of Chemistry
- University of Basel
- 4056 Basel
- Switzerland
| | - Manfred Heuberger
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | | | | | - Luciano F. Boesel
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| | - Lukas J. Scherer
- Empa, Swiss Federal Laboratories for Materials Science and Technology
- 9014 St. Gallen
- Switzerland
| |
Collapse
|
14
|
Blanchard NE, Naik VV, Geue T, Kahle O, Hegemann D, Heuberger M. Response of Plasma-Polymerized Hexamethyldisiloxane Films to Aqueous Environments. Langmuir 2015; 31:12944-12953. [PMID: 26451512 DOI: 10.1021/acs.langmuir.5b03010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Thin plasma polymer films were deposited in hexamethyldisiloxane (HMDSO) and HMDSO/O2 low-pressure discharges and their chemical structures analyzed using infrared (IR) spectroscopy and neutron reflectometry (NR). The (plasma-polymerized) ppHMDSO film exhibits hydrophobic, poly(dimethylsiloxane)-like properties, while the retention of carbon groups is reduced by O2 addition, yielding a more inorganic, hydrophilic ppSiOx film. Both films show a minor (vertical) density gradient perpendicular to the substrate, where the exposed film surface seems to be more oxidized, indicating oxidative aging reactions upon contact with air. The hydration and water uptake abilities of the films in aqueous environments were investigated in humid environments using ellipsometry, NR in D2O, and multiple transmission-reflection IR measurements after equilibration of the films in water.
Collapse
Affiliation(s)
- Noemi E Blanchard
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen, Switzerland
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , 8093 Zürich, Switzerland
| | - Vikrant V Naik
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , 8093 Zürich, Switzerland
| | - Thomas Geue
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut , 5232 Villigen, Switzerland
| | - Olaf Kahle
- Fraunhofer Research Institution for Polymeric Materials and Composites PYCO , 14513 Teltow, Germany
| | - Dirk Hegemann
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen, Switzerland
| | - Manfred Heuberger
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 9014 St. Gallen, Switzerland
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , 8093 Zürich, Switzerland
| |
Collapse
|
15
|
von Goetz N, Lorenz C, Windler L, Nowack B, Heuberger M, Hungerbühler K. Migration of Ag- and TiO2-(Nano)particles from textiles into artificial sweat under physical stress: experiments and exposure modeling. Environ Sci Technol 2013; 47:9979-9987. [PMID: 23786648 DOI: 10.1021/es304329w] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Engineered nanoparticles (ENP) are increasingly used to functionalize textiles taking advantage, e.g., of the antimicrobial activity of silver (Ag)-ENP or the UV-absorption of titania (TiO2)-ENP. Mobilization and migration of ENPs from the textile into human sweat can result in dermal exposure to these nanoobjects and their aggregates and agglomerates (NOAA). In this study we assessed exposure to NOAA migrating from commercially available textiles to artificial sweat by an experimental setup that simulates wear-and-tear during physical activity. By combining physical stress with incubation in alkaline and acidic artificial sweat solutions we experimentally realized a worst case scenario for wearing functionalized textiles during sports activities. This experimental approach is not limited to NOAA, but can be used for any other textile additive. Out of four investigated textiles, one T-shirt and one pair of trousers with claimed antimicrobial properties were found to release Ag <450 nm in detectable amounts (23-74 μg/g/L). Textiles containing TiO2 for UV protection did not release significant amounts of TiO2 <450 nm, but the antimicrobial T-shirt released both TiO2 and Ag <450 nm. The silver was present in dissolved and particulate form, whereas TiO2 was mainly found as particulate. On the basis of our experimental results we calculated external dermal exposure to Ag and TiO2 for male and female adults per use. For silver, maximal amounts of 17.1 and 8.2 μg/kg body weight were calculated for total and particulate Ag <450 nm, respectively. For TiO2, the exposure levels amount to maximal 11.6 μg/kg body weight for total (mainly particulate) TiO2. In comparison with other human exposure pathways, dermal exposure to NOAA from textiles can be considered comparably minor for TiO2-NOAA, but not for Ag-NOAA.
Collapse
Affiliation(s)
- N von Goetz
- ETH Zürich, Institute for Chemical and Bioengineering, 8093 Zürich, Switzerland.
| | | | | | | | | | | |
Collapse
|
16
|
Perret E, Reifler FA, Hufenus R, Bunk O, Heuberger M. Modified Crystallization in PET/PPS Bicomponent Fibers Revealed by Small-Angle and Wide-Angle X-ray Scattering. Macromolecules 2012. [DOI: 10.1021/ma3021213] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Edith Perret
- Laboratory for Advanced Fibers,
Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen,
Switzerland
| | - Felix A. Reifler
- Laboratory for Advanced Fibers,
Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen,
Switzerland
| | - Rudolf Hufenus
- Laboratory for Advanced Fibers,
Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen,
Switzerland
| | - Oliver Bunk
- Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Manfred Heuberger
- Laboratory for Advanced Fibers,
Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen,
Switzerland
| |
Collapse
|
17
|
Lorenz C, Windler L, von Goetz N, Lehmann RP, Schuppler M, Hungerbühler K, Heuberger M, Nowack B. Characterization of silver release from commercially available functional (nano)textiles. Chemosphere 2012; 89:817-24. [PMID: 22677521 DOI: 10.1016/j.chemosphere.2012.04.063] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/25/2012] [Accepted: 04/30/2012] [Indexed: 05/18/2023]
Abstract
Silver, both in the nano as well as in other forms, is used in many applications including antimicrobial textiles. Washing of such textiles has already been identified as an important process that results in the release of silver into wastewater. This study thus investigated the release of silver from eight different commercially available silver-textiles during a washing and rinsing cycle. The silver released was size-fractionated and characterized using electron microscopy. In addition, the antimicrobial functionality of the textiles was tested before and after washing. Three of the textiles contained nanosized silver (labeled or confirmed by manufacturers' information), another used a metallic silver wire and four contained silver in undeclared form. The initial silver content of the textiles was between 1.5 and 2925mg Ag/kg. Only four of the investigated textiles leached detectable amounts of silver, of which 34-80% was in the form of particles larger than 450nm. Microscopic analysis of the particles released in the washing solutions identified Ti/Si-AgCl nanocomposites, AgCl nanoparticles, large AgCl particles, nanosilver sulfide and metallic nano-Ag, respectively. The nanoparticles were mainly found in highly agglomerated form. The identified nanotextiles showed the highest antimicrobial activity, whereas some of the other textiles, e.g. the one with a silver wire and the one with the lowest silver content, did not reduce the growth of bacteria at all. The results show that different silver textiles release different forms of silver during washing and that among the textiles investigated AgCl was the most frequently observed chemical form in the washwater.
Collapse
Affiliation(s)
- C Lorenz
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, 9014 St. Gallen, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Windler L, Lorenz C, von Goetz N, Hungerbühler K, Amberg M, Heuberger M, Nowack B. Release of titanium dioxide from textiles during washing. Environ Sci Technol 2012; 46:8181-8. [PMID: 22746197 DOI: 10.1021/es301633b] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nano-TiO(2) has the highest production of all nanomaterials, and pigment-TiO(2) is a commodity used on the million tons/year scale. Information on the release of TiO(2) from consumer products is therefore an important part of analyzing the potential environmental exposure to TiO(2). For this study, we investigated the release of TiO(2) from six different functional textiles during washing. TiO(2) is used in textiles because of its UV-absorbing properties and as pigment. Analysis of fiber cross sections showed that the TiO(2) was contained in the fiber matrix. The sun-protection textiles had Ultraviolet Protection Factors that were between 58 and 6100 after washing and therefore above the labeled factor of 50+. Five of the textiles (sun-protection clothes) released low amounts of Ti (0.01 to 0.06 wt % of total Ti) in one wash cycle. One textile (with antimicrobial functionality) released much higher amounts of Ti (5 mg/L, corresponding to 3.4 wt % of total Ti in one wash cycle). Size fractionation showed that about equal amounts were released as particles below and above 0.45 μm. After 10 washings, only in two textiles significantly lower Ti contents were measured. Electron microscopy showed that the TiO(2) particles released into washing solution had a roundish appearance with primary particle sizes between 60 and 350 nm that formed small aggregates with up to 20 particles. The results indicate that functional textiles release some TiO(2) particles, but that the amounts are relatively low and mostly not in the nanoparticulate range.
Collapse
Affiliation(s)
- L Windler
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, 9014 St. Gallen, Switzerland
| | | | | | | | | | | | | |
Collapse
|
19
|
|
20
|
Abstract
We report on design and performance of an extended surface forces apparatus (eSFA) built into a pressurized system. The aim of this instrument is to provide control over static pressure and temperature to facilitate direct surface force experiments in equilibrium with fluids at different loci of their phase diagram. We built an autoclave that can bear a miniature eSFA. To avoid mechanical or electrical feedtroughs the miniature apparatus uses an external surface coarse approach stage under ambient conditions. The surface separation is thus pre-adjusted to approximately ~3 μm before sliding the apparatus into the autoclave. Inside the autoclave, the surface separation can be further controlled with a magnetic drive at sub-Ångstrom precision over a 14 μm range. The autoclave pressure can then be set and maintained between 20 mbar and 170 bars with few mbar precision. The autoclave is connected to a specially designed pressurization system to precondition the fluids. The temperature can be controlled between -20 and 60 °C with few mK precision. We demonstrate the operation of the instrument in the case of gaseous or liquid carbon dioxide. Thanks to a consequent decoupling of the eSFA mechanical loop from the autoclave structure, the obtained measurement stability and reproducibility, at elevated pressures, is comparable to the one established for the conventional eSFA, operated under ambient conditions.
Collapse
Affiliation(s)
- E Schurtenberger
- Empa, Materials Science and Technology, CH-9014 St. Gallen, Switzerland
| | | |
Collapse
|
21
|
Lischer S, Körner E, Balazs DJ, Shen D, Wick P, Grieder K, Haas D, Heuberger M, Hegemann D. Antibacterial burst-release from minimal Ag-containing plasma polymer coatings. J R Soc Interface 2011; 8:1019-30. [PMID: 21247951 DOI: 10.1098/rsif.2010.0596] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Biomaterials releasing silver (Ag) are of interest because of their ability to inhibit pathogenic bacteria including antibiotic-resistant strains. In order to investigate the potential of nanometre-thick Ag polymer (Ag/amino-hydrocarbon) nanocomposite plasma coatings, we studied a comprehensive range of factors such as the plasma deposition process and Ag cation release as well as the antibacterial and cytocompatible properties. The nanocomposite coatings released most bound Ag within the first day of immersion in water yielding an antibacterial burst. The release kinetics correlated with the inhibitory effects on the pathogens Pseudomonas aeruginosa or Staphylococcus aureus and on animal cells that were in contact with these coatings. We identified a unique range of Ag content that provided an effective antibacterial peak release, followed by cytocompatible conditions soon thereafter. The control of the in situ growth conditions for Ag nanoparticles in the polymer matrix offers the possibility to produce customized coatings that initially release sufficient quantities of Ag ions to produce a strong adjacent antibacterial effect, and at the same time exhibit a rapidly decaying Ag content to provide surface cytocompatibility within hours/days. This approach seems to be favourable with respect to implant surfaces and possible Ag-resistance/tolerance built-up.
Collapse
Affiliation(s)
- Stefanie Lischer
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St.Gallen, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Perret E, Balmer TE, Heuberger M. Self-consistent algorithm for calibrating spectrometers to picometer accuracy over the entire wavelength range. Appl Spectrosc 2010; 64:1139-1144. [PMID: 20925984 DOI: 10.1366/000370210792973659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Spectrometer calibration accuracies are of high importance for a wide range of applications. Typically, one calibrates the spectrometer with a calibration lamp, providing distinct and well-defined calibration lines. However, for small spectral ranges, where only two calibration lines are present, the calibration becomes inaccurate. We present a high-precision nonlinear wavelength calibration method, which is based on two or more reference lines from a calibration lamp. The additional key element introduced is a Fabry-Perot multilayer structure that yields multiple sharp transmission maxima of similar intensity over the full spectrometer range under broad-band illumination (e.g., white-light source). An iterative algorithm is put forward to obtain a self-consistent calibration of picometer precision over the full spectrometer range. In regions distant from calibration lines the accuracy is enhanced by at least a factor of two compared to conventional methods.
Collapse
Affiliation(s)
- Edith Perret
- Paul Scherrer Institut, 5232 Villigen, Switzerland.
| | | | | |
Collapse
|
23
|
Perret E, Nygård K, Satapathy DK, Balmer TE, Bunk O, Heuberger M, van der Veen JF. X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement. J Synchrotron Radiat 2010; 17:465-472. [PMID: 20567078 PMCID: PMC2927908 DOI: 10.1107/s0909049510014858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2009] [Accepted: 04/22/2010] [Indexed: 05/29/2023]
Abstract
An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known structure) and the layered liquid in between them (of unknown structure) interfere with one another, making X-ray reflectivity highly sensitive to the liquid's density profile along the confinement direction. An expression for the reflected intensity as a function of momentum transfer is given. The total structure factor intensity for the liquid-filled confinement device is derived as a sum of contributions from the inner and outer crystal terminations. The method presented readily distinguishes the confined liquid from the liquid adsorbed on the outer mica surfaces. It is illustrated for the molecular liquid tetrakis(trimethyl)siloxysilane, confined by two mica surfaces at a distance of 8.6 nm.
Collapse
Affiliation(s)
- Edith Perret
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Kim Nygård
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | | | | | - Oliver Bunk
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | | | - J. Friso van der Veen
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- ETH Zürich, 8093 Zürich, Switzerland
| |
Collapse
|
24
|
Perret E, Nygård K, Satapathy DK, Balmer TE, Bunk O, Heuberger M, van der Veen JF. Molecular liquid under nanometre confinement: density profiles underlying oscillatory forces. J Phys Condens Matter 2010; 22:235102. [PMID: 21393761 DOI: 10.1088/0953-8984/22/23/235102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ultrathin (<12 nm) films of tetrakis(trimethyl)siloxysilane (TTMSS) have been confined by atomically flat mica membranes in the presence and absence of applied normal forces. When applying normal forces, discrete film thickness transitions occur, each involving the expulsion of TTMSS molecules. Using optical interferometry we have measured the step size associated with a film thickness transition (7.5 Å for compressed, 8.4 Å for equilibrated films) to be smaller than the molecular diameter of 9.0 Å. Layering transitions with a discrete step size are commonly regarded as evidence for strong layering of the liquid's molecules in planes parallel to the confining surfaces and it is assumed that the layer spacing equals the measured periodicity of the oscillatory force profile. Using x-ray reflectivity (XRR), which directly yields the liquid's density profile along the confinement direction, we show that the layer spacing (10-11 Å) proves to be on average significantly larger than both the step size of a layering transition and the molecular diameter. We observe at least one boundary layer of different electron density and periodicity than the layers away from the surfaces.
Collapse
Affiliation(s)
- Edith Perret
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | | | | | | | | | | | | |
Collapse
|
25
|
Sannomiya T, Balmer TE, Hafner C, Heuberger M, Vörös J. Optical sensing and determination of complex reflection coefficients of plasmonic structures using transmission interferometric plasmonic sensor. Rev Sci Instrum 2010; 81:053102. [PMID: 20515119 DOI: 10.1063/1.3405912] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The combination of interferometry and plasmonic structure, which consists of gold nanoparticle layer, sputter coated silicon oxide spacer layer, and aluminum mirror layer, was studied in transmission mode for biosensing and refractive index sensing applications. Because of the interferometric nature of the system, the information of the reflection amplitude and phase of the plasmonic layer can be deduced from one spectrum. The modulation amplitude in the transmission spectrum, caused by the interference between the plasmonic particle layer and the mirror layer, increases upon the refractive index increase around the plasmonic particles due to their coherent backscattering property. Our proposed evaluation method requires only two light sources with different wavelengths for a stable self-referenced signal, which can be easily and precisely tuned by a transparent spacer layer thickness. Unlike the standard localized surface plasmon sensors, where a sharp resonance peak is essential, a broad band plasmon resonance is accepted in this method. This leads to large fabrication tolerance of the plasmonic structures. We investigated bulk and adsorption layer sensitivities both experimentally and by simulation. The highest sensitivity wavelength corresponded to the resonance of the plasmonic particles, but useful signals are produced in a much broader spectral range. Analysis of a single transmission spectrum allowed us to access the wavelength-dependent complex reflection coefficient of the plasmonic particle layer, which confirmed the reflection amplitude increase in the plasmonic particle layer upon molecular adsorption.
Collapse
Affiliation(s)
- Takumi Sannomiya
- Department of Information Technology and Electrical Engineering, Laboratory of Biosensors and Bioelectronics, ETH Zurich, Zurich 8092, Switzerland.
| | | | | | | | | |
Collapse
|
26
|
Kraft P, Bunk O, Reifler FA, Hufenus R, Heuberger M, Pfeiffer F. One-dimensional small-angle X-ray scattering tomography of dip-coated polyamide 6 monofilaments. J Synchrotron Radiat 2010; 17:257-262. [PMID: 20157280 DOI: 10.1107/s0909049509054156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Accepted: 12/15/2009] [Indexed: 05/28/2023]
Abstract
A synchrotron study is presented in which the concept of one-dimensional tomographic reconstruction of small-angle X-ray scattering patterns is applied to investigate polyamide 6 monofilaments, dip-coated with alumina particles. The filaments are scanned with a focused synchrotron beam and the resulting scattering patterns are recorded with a PILATUS 2M detector. The reconstructed sequence of SAXS images reflects the local nanostructure variation along the filament radius. In particular, the influence of coating process parameters on the polyamide 6 is investigated.
Collapse
Affiliation(s)
- P Kraft
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
| | | | | | | | | | | |
Collapse
|
27
|
Abstract
The widespread use of silver nanoparticles (Ag-NPs) in commercial products, especially textiles, will likely result in an unknown spread of Ag into the environment. The quantification and characterization of the Ag released from nano-Ag-products is an important parameter needed to predict the effect of Ag-NPs on the environment. The aim of this study was to determine the amount and the form of Ag released during washing from nine fabrics with different ways of silver incorporation into or onto the fibers. The effect of pH, surfactants, and oxidizing agents was evaluated. The results show that little dissolution of Ag-NPs occurs under conditions relevant to washing (pH 10) with dissolved concentrations 10 times lower than at pH 7. However, bleaching agents such as hydrogen peroxide or peracetic acid (formed by the perborate/TAED system) can greatly accelerate the dissolution of Ag. The amount and form of Ag released from the fabrics as ionic and particulate Ag depended on the type of Ag-incorporation into the textile. The percentage of the total silver emitted during one washing of the textiles varied considerably among products (from less than 1 to 45%). In the washing machine the majority of the Ag (at least 50% but mostly >75%) was released in the size fraction >450 nm, indicating the dominant role of mechanical stress. A conventional silver textile did not show any significant difference in the size distribution of the released silver compared to many of the textiles containing nano-Ag. These results have important implications for the risk assessment of Ag-textiles and also for environmental fate studies of nano-Ag, because they show that under conditions relevant to washing, primarily coarse Ag-containing particles are released.
Collapse
Affiliation(s)
- L Geranio
- Technology and Society Laboratory, and Laboratory of Advanced Fibers, Empa - Swiss Federal Laboratories for Materials Testing and Research, CH 9014 St. Gallen, Switzerland
| | | | | |
Collapse
|
28
|
Gaan S, Rupper P, Salimova V, Heuberger M, Rabe S, Vogel F. Thermal decomposition and burning behavior of cellulose treated with ethyl ester phosphoramidates: Effect of alkyl substituent on nitrogen atom. Polym Degrad Stab 2009. [DOI: 10.1016/j.polymdegradstab.2009.03.017] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
29
|
Nowak D, Heuberger M, Zäch M, Christenson HK. Thermodynamic and kinetic supercooling of liquid in a wedge pore. J Chem Phys 2008; 129:154509. [DOI: 10.1063/1.2996293] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
30
|
Abstract
We have measured the adsorption isotherms of water on a single surface of freshly cleaved mica with K+ on the surface, and on mica where the K+ has been exchanged for H+. Using a very sensitive interferometric technique, we have found a significant difference between the two isotherms at submonolayer coverage, for relative vapor pressures p/p0 < 0.5. The K+-mica isotherm shows a pronounced convexity, suggesting distinct adsorption sites, whereas the H+-mica isotherm is flatter. The two isotherms converge above monolayer coverage. The results give a graphic demonstration of the importance of nanoscale surface heterogeneities for vapor adsorption at submonolayer coverage.
Collapse
Affiliation(s)
- T E Balmer
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | | | | | | |
Collapse
|
31
|
Balmer TE, Heuberger M. Precision thickness and refractive index imaging of molecular films. Rev Sci Instrum 2007; 78:093105. [PMID: 17902945 DOI: 10.1063/1.2777369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We present an interferometric contrasting technique that allows visualizing the thickness and refractive index of a molecular film being part of an optical multilayer structure (etalon). Small wavelength shifts of the comblike etalon spectrum are transformed into measurable intensity variations using a second reference etalon (optical correlator), illuminated in series. A charge-coupled device camera acting as two-dimensional photometer is utilized to measure the optical spectral correlation (OSC) image. The performance of the here proposed optical spectral correlation method is demonstrated using very thin confined liquid films. We give a detailed signal-to-noise analysis. Subangstrom film thickness resolution is experimentally verified with single exposure images acquired at frame rates comparable to video standards (approximately 25 Hz). Finally, we describe the calibration procedures necessary to obtain an absolute quantification of the OSC image.
Collapse
Affiliation(s)
- T E Balmer
- Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | | |
Collapse
|
32
|
|
33
|
Heuberger M, Drobek T, Spencer ND. Interaction forces and morphology of a protein-resistant poly(ethylene glycol) layer. Biophys J 2005; 88:495-504. [PMID: 15501935 PMCID: PMC1305026 DOI: 10.1529/biophysj.104.045443] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Accepted: 10/15/2004] [Indexed: 11/18/2022] Open
Abstract
The molecular interactions on a protein-resistant surface coated with low-molecular-weight poly(ethylene glycol) (PEG) copolymer brushes are investigated using the extended surface forces apparatus. The observed interaction force is predominantly repulsive and nearly elastic. The chains are extended with respect to the Flory radius, which is in agreement with qualitative predictions of scaling theory. Comparison with theory allows the determination of relevant quantities such as brush length and adsorbed mass. Based on these results, we propose a molecular model for the adsorbed copolymer morphology. Surface-force isotherms measured at high resolution allow distinctive structural forces to be detected, suggesting the existence of a weak equilibrium network between poly(ethylene glycol) and water--a finding in accordance with the remarkable solution properties of PEG. The occurrence of a fine structure is interpreted as a water-induced restriction of the polymer's conformational space. This restriction is highly relevant for the phenomenon of PEG protein resistance. Protein adsorption requires conformational transitions, both in the protein as well as in the PEG layer, which are energetically and kinetically unfavorable.
Collapse
Affiliation(s)
- M Heuberger
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Zürich, Switzerland.
| | | | | |
Collapse
|
34
|
Abstract
We focus on the role of water in a protein-resistant poly(ethylene glycol) (PEG) layer. Using the combination of two experimental techniques, namely, the extended surface forces apparatus and the quartz crystal microbalance, we demonstrate that the water content inside these surface-grafted layers is over 80 vol % while the conformational space of the PEG chains is significantly modulated in water. Discrete and reversible film thickness transitions of 1.25 A size are shown to occur when the film is compressed, a finding that suggests a high degree of organization in the PEG/water complex. The results are discussed in terms of the excellent protein resistance properties of this type of surface.
Collapse
|
35
|
|
36
|
Hoppe H, Heuberger M, Klein J. Self-similarity and pattern selection in the roughening of binary liquid films. Phys Rev Lett 2001; 86:4863-4866. [PMID: 11384367 DOI: 10.1103/physrevlett.86.4863] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2001] [Indexed: 05/23/2023]
Abstract
Films of spinodally decomposing binary liquid mixtures show transient wetting of both confining interfaces by one of the phases, and rupture, with characteristic wavelength lambda(c) and time tau(rupture), leading to flat droplets of the nonwetting phase encapsulated by the wetting phase. Over the entire range of film thicknesses d approximately 100-3500 nm, we find tau(rupture)~d(1.01+/-0.08), indicating film structures that scale self-similarly with d, and find also that lambda(c) approximately 60d(0.97+/-0.03), the large prefactor suggesting a rupture wavelength which minimizes the interfacial tension of the roughened film.
Collapse
Affiliation(s)
- H Hoppe
- Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | |
Collapse
|
37
|
Abstract
Knowing the behavior of a fluid in small volumes is essential for the understanding of a vast array of common problems in science, such as biological interactions, fracture propagation, and molecular tribology and adhesion, as well as pressure solvation and other geophysical processes. When a fluid is confined, its phase behavior is altered and excluded-volume effects become apparent. Pioneering measurements performed with the surface forces apparatus have revealed so-called structural or oscillatory solvation forces as well as the occurrence of a finite shear stress, which was interpreted as a solidification transition. Here, we report measurements obtained with an extended surface forces apparatus, which makes use of fast spectral correlation to gain insight into the behavior of a thin film of cyclohexane confined within attoliter volumes, with simultaneous measurement of film thickness and refractive index. With decreasing pore width, cyclohexane is found to undergo a drastic transition from a three-dimensional bulk fluid to a two-dimensional adsorbate with strikingly different properties. Long-range density fluctuations of unexpected magnitude are observed.
Collapse
Affiliation(s)
- M Heuberger
- Laboratory for Surface Science and Technology, ETH Zentrum, CH-8092 Zürich, Switzerland.
| | | | | |
Collapse
|
38
|
|
39
|
Israelachvili J, Giasson S, Kuhl T, Drummond C, Berman A, Luengo G, Pan JM, Heuberger M, Ducker W, Alcantar N. Some fundamental differences in the adhesion and friction of rough versus smooth surfaces. Thinning Films and Tribological Interfaces, Proceedings of the 26th Leeds-Lyon Symposium on Tribology 2000. [DOI: 10.1016/s0167-8922(00)80107-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
40
|
Affiliation(s)
- M. Heuberger
- Materials Department, ETH, 8092 Zürich, Switzerland, Physical Chemistry Department, Complutense University, Madrid, Spain 28040, and Department Chem. Eng. and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - G. Luengo
- Materials Department, ETH, 8092 Zürich, Switzerland, Physical Chemistry Department, Complutense University, Madrid, Spain 28040, and Department Chem. Eng. and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - J. N. Israelachvili
- Materials Department, ETH, 8092 Zürich, Switzerland, Physical Chemistry Department, Complutense University, Madrid, Spain 28040, and Department Chem. Eng. and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106
| |
Collapse
|
41
|
Affiliation(s)
- Manfred Heuberger
- Laboratory for Surface Science and Technology, ETH, CH-8092 Zürich, Switzerland
| | - Carlos Drummond
- Department of Chemical Engineering, and Materials Department, University of California, Santa Barbara, California 93106
| | - Jacob Israelachvili
- Department of Chemical Engineering, and Materials Department, University of California, Santa Barbara, California 93106
| |
Collapse
|
42
|
Schmidhammer H, Smith CF, Dalkner E, Erlach D, Heuberger M, Rollinger JM. (-)-N,N'-but-2-ene-1,4-diylbimorphinans. Pharmazie 1991; 46:101-2. [PMID: 1649476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
N,N'-But-2-ene-1,4-diylbimorphinans 1-3 have been synthesized and pharmacologically evaluated. Bimorphinans 1 and 3 show opioid antagonist activity and preference for mu and kappa opioid receptors in mouse vas deferens and guinea pig ileum preparations.
Collapse
Affiliation(s)
- H Schmidhammer
- Institute of Organic and Pharmaceutical Chemistry, University of Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|
43
|
Behrman EC, Amarakoon VRW, Axelson SR, Bhargava A, Brooks KG, Burdick VL, Carson SW, Corah NL, Cordaro JF, Cormack AN, DiCarlo DG, Dwivedi A, Fischman GS, Friel J, Hanagan MJ, Hexemer RL, Heuberger M, Hong KS, Hsu JY, Hsu WD, Johnson PF, LaCourse WC, LaGraff JR, Lakshminarasimha M, Laughner JW, Longobardo AV, Malone PF, McCluskey PH, McPherson DM, Mroz TJ, Rabidoux CW, Reed JS, Sainamthip P, Sanchez SC, Sheckler CA, Schulze WA, Seth VK, Shelby JE, Shieh SHM, Simmins JJ, Simpson JC, Snyder RL, Swiler D, Taylor JAT, Udaykumar R, Varshneya AK, Vitch SM, Votava WE. Synthesis, Characterization, and Fabrication of High Temperature Superconducting Oxides. ACTA ACUST UNITED AC 1987. [DOI: 10.1111/j.1551-2916.1987.tb00118.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|